Originals vs. Licensed reproductions?  

Wherever possible always buy...
Wherever possible always buy original,it should hold its value at the very minimum.

Another way to look at it might be drawn from a parallel in the world
of collectible books. A first edition is infinitely more valuable then the 33rd printing or even the second print run

originals, originals, originals...
well said, BTM. in my experience, most current productions are inferior to originals in both nostalgia AND quality. Herman Miller in particular. Vitra might be the one exception, but paying $7000 for a Vitra-produced Nelson daybed is a bit ridiculous to me as their exorbitant pricing is somewhat of a slap in the face to the spirit of the original design.

Originals
always win. That being said, I have a few new Herman Miller pieces. I like them, but the originals have the "soul." I decided on a new HM lounge and ottoman though for functional reasons. I didn't want to go through the paranoia of the shockmounts failing (as they often do) because it was a piece I planned on using the hell out of.
Vintage shells are easy enough to get repaired, tables you don't use like a chair, so those are best vintage.
I have a new Nelson bench. It's nice. After seven years it's starting to get some wear finally.

Absolutely the 7k is a slap in the face
and when you go to the Vitra store in the meat-packing district of Manhattan and see the way the Vitra items are displayed with those endless yards of empty and incredibly priced manhattan rental real estate surrounding single items like in a museum, you get an idea why some of the stuff in the store is priced as such. Relocate the store to White Plains and they could easily shave their prices by 30%.
But of course a White Plains location would be ever so de classe 🙂

A question about the fake Nelson benches
I'm considering a black 4 ft bench as a coffee table.
Can someone explain the actual different between the knockoffs and the Nelson/Herman Miller benches?
Thanks!

Lunchbox definitely can. He...
Lunchbox definitely can. He has had both. Lunchables?

aye, that I can barry...
i bought a knockoff Nelson bench a couple of years ago. i was short on tables(and overloaded with chairs) at the time and as interested in answering your very question as actually using the bench. as i already had a coffee table, i figured at worst i could find a spot for it and cover it with plants... which is exactly what i ended up doing. to answer your question, i can't speak for every knockoff but the differences in mine were/are drastic... finish firstly along with dimensional discrepancies. the craftsmanship and finish were plainly lacking and it didn't accomplish the 'streamlined' look which contributes so to the elegance of the original design. that said, i would never purchase a vintage or current HM production if i were planning to cover it with plants. and i've since purchased a vintage Nelson bench and passed along the repro as i generally found the whole idea(knockoffs) wasteful. not telling you to steer clear as you have to make that decision. but these days i carry a 'vintage if at all possible' policy when purchasing furnishings.

Technically
I'm with Whitespike - I buy vintage whenever I can as long as the vintage piece can handle daily use. But I sprang for new with the Eames LCW for fear of the shockmounts and I got a new Eames lounge.
But technically speaking, the new Eames lounge IS an original, as it has never been out of production. Plus, with new pieces, you get to add your own history to the piece. Its killing me that my lounge cushions look BRAND new! Lol. I want them to be all old and beat up like a vintage 60's piece.

best of both
I know what you mean about the new cushions. I bought a heavily used floor model that was from the mid 90s. It came nice and wrinkly and with the strength of new shock mounts.

*sigh*
I want to leave a sack of bowling balls on the seat when I'm not around... I guess it will come soon enough 🙂

i'm not completely against...
i'm not completely against 'new' originals. you were quite right to point out the fact that current HM and Knoll productions are indeed originals, LS. whitespike's Nelson bench is quite nice. but as you both alluded to, a large part of the nostalgia vintage pieces carry is due to wear(patina). that said, logic always points to function which is why i own a Modernica version of the Nelson daybed in kid-friendly naugahyde and plan to opt for 'new' when I make my next sofa purchase.

comparison
they have some pretty good articles here for comparing originals with replicas: http://regencyshop.com/articles.html