Mulhauser's Mr. Chair for Plycraft  

it's a good chair if you're...
it's a good chair if you're concerned about the structure. but i prefer the 670 because of the timeless appeal. the mulhauser chair's got too much buttons for my taste. i have never sat on one (mulhauser) but the eames is the most comfortable chair i have ever sat on. i fall asleep each time. but i like the rarity of the mulhauser.

If I'm being honest...
The more I've looked at my L & O, the more it smacks of corporate design. This is not to say I don't love it. It's a beautiful chair, and very comfortable. But it's just as popular in the commercial realm as it is residential, probably moreso. "The Executive Lounge Chair" is its nickname after all. And then there's the cliche factor, etc...
The Mr. Chair to me looks more relevant for residential settings than the L & O. Just my opinion. But I take this stuff pretty damn seriously and it's taken me a while to come to this conclusion. So whether anyone agrees with it or not, I'm convinced.

Having only seen pictures....
I would venture to guess that the quality of the Plycraft chair is not comparable to Herman Miller. The veneers look rather cheap to me, and the bases unrefined. Aesthetically, I believe there are other, less common Plycraft lounge designs that are more appealing than "Mr. Chair", in my opinion. If I were to get a Plycraft chair, I would not pay more than a few hundred for one in good condition.
I guess there is only one way to find out how it truly compares to the Eames 670.

Fair enough, woody...
I'm sure that would be the most common argument for the L & O. I'm sure the Plycraft materials aren't the same quality. And I would have to agree that the Mr. Chair is less refined aesthetically. But at the same time, that makes it more interesting to me. I get tired of every piece of design around me looking more suited for a showroom than my living room.
As for it in comparison to later Plycraft chairs, I don't agree at all. The rest of the Plycraft lounge chairs are nothing more than Eames Lounge knockoffs. The original was Mulhauser's take on the plywood lounge form. And Mulhauser was no lightweight.

Sizes
There are two sizes in this design of which you have the smaller one pictured. The larger one is the Mr chair and would be a better comparable to the 670.

I've seen
I've seen dozens of Plycraft chairs, including Mr Chair and the quality just isn't the same. Which is not the same as saying they aren't great chairs - but you're comparing apples to oranges.
I agree with Luncbhbox's concern about looking corporate and cliched. I, of course, have fallen into that cliche myself, but I don't begrudge others from choosing things that are more personal. Personally I would look for the rare Mulhauser lounge chair that is on 4 legs, not on the swivel base. Or I would search out some of the more esoteric and weird variations on the plywood lounges.
Or if quality is an issue you might try some of the other lesser known lounge chairs - I've seen quite a few Wegner Poppa Bears on 1st dibs that aren't (surprisingly) outrageous.

I love this chair, but have...
I love this chair, but have never sat in one myself. It's quirkiness has always appealed to me.
It doesn't have to be as refined you know. Original Prouve is not among other things. It has it's place and Mulhauser was/is underrated ... he did design the coconut chair. Can't be all bad!

There is more to this story...
In retrospect, I will say that living with a newer version of the L & O has curbed my enthusiasm for the design... which is a bit bogus really. In reality, that shouldn't reflect on the design but rather the manufacturer. The modern day Herman Miller company has done nothing but piss all over the Eames catalogue. It's really a shame. Let's delve into it a bit, shall we...
1. The current 670/671 cushions are overstuffed and all the standard veneer finishes are just plain gross.
2. The current shell chairs are nothing short of an abomination.
3. All of the current Plywood Series designs fail due to the veneer finishes already mentioned.
4. The Time Life stools are horrid due to the fugly finishes already mentioned.
5. The Aluminum Group and Soft Pad Series look silly with the newer five star base.
The real shame of this all is the contradictory nature of Herman Miller's actions from one design to the next. The lack of changes to the L & O are really quite shocking when one considers the plethora of alterations to the shell chairs. There's little doubt that Father Charles would've made the necessary adjustments to the 670/671 if he were with us today as he was never one afraid of change when confronted with newer, better materials and/or techniques. But since Herman Miller knows full well that people will buy the 670/671 regardless, they are quite content to continue on manufacturing a flawed design. And I would wager they are quite pleased to be creating a repair/restoration market as well.
While I will admit that I don't know what else I should expect from a business with shareholders, it still leaves a very bad taste in my mouth and in the end reinforces my policy of buying vintage if at all possible.

My thought on veneers
I believe that good ones are harder to come by these days, perhaps due to environmental factors. Looking at many of the current issues of modern (and contemporary) designs, the quality of the veneers has certainly gone down.
I purchased a new LCW several years ago in cherry finish, and it looks beautiful now. Obviously doesn't have the patina of a 50-year old piece yet....
Regarding the Time Life stools, I think the finish on the new ones is nice. They are actually much darker than vintage pieces. The problem lies in the construction. They are just not put together as well.

I did some quick research
last sunday...bad weather in NY gave me a rare day off.
I just inherited a 'mr chair'. It was headed for the Sally Army. I brought
it home for sentimental reasons. Bought in Corvalis Washington years ago.
I have the original receipt. I'll get a decent pic if i ever see it in good daylight.
It is very different than the one posted above but the foil tag under says
'mr chair'.
I also like the one Lunchbox is referring to. (Except for the replacement
leather choice on the back)
Here are a couple links i found useful without much effort.
http://boards.gomod.com/eve/forums/a/tpc/f/2336007761/m/2901027314

A blog devoted
to all things Plycraft...
http://suburbanpioneers.blogspot.com/search?q=plycraft&max-results=20

Maybe
Maybe you just shouldn't buy Herman Miller products - they seem to upset you.
I hate when people invoke the Ghost of the Eames Past. Just to clarify - it's not like Charles just made the 670/671 and disappeared. He was alive for almost 20 of its 50 year life thus far. It was well known that the shockmounts fail - one of the Eames Office members speak to it in the Eames Lounge exhibition catalog. I still maintain- as it would seem Charles did- that the majority of the chairs hold, and the minority that do fail are being over-reported. I will definitely conceed that the newer chairs are overstuffed and require far too long to 'break in'.
As for your other complaints - I think you're confusing "change" with "time". For example - I have 4 fiberglass shell chairs at my table that range from '56-'93. The '56 one looks beautiful, rich, and patina-ed. The '93 one looks cheap and plastic by comparison.
My '46 ash DCM has the same pattern of veneer as my '06 ash DCM - the older one is just older, more beat up, and more worn.

Cheap looking veneers
An example:

I'm not referring to veneer quality...
I just don't like the finishes. The ash is too light. The walnut is too dark. They don't even look natural. The best looking finish is cherry and cherry is one of my least favorite woods. Their finishes don't look any better to me than many we would call cheap.
Lucifer, you're right. I shouldn't(and don't now other than one LTR) own newer Herman Miller products. But patina is not the issue. A Zenith fiberglass shell chair isn't valued more highly because it's aged well. It's sought after because the fibers are much more apparent than the later shells. The fiberglass is what makes the chairs really interesting. The fact that Herman Miller has omitted this material and changed the polymer as well is ridiculous. They should've just discontinued the design if they were concerned about being eco-friendly.