Hi Diki
Its amazing how much difference a year or more makes, the original demos were from about November 2005, which was only a few months after OAS 7 had been released.
The exception was the Live Jazz Demo, which was about a year later and featured a Beta version of the OAA, (You probably noticed the imbalance of the sounds)
The style used was the Tyros 2 Bebop with EzDruumer VST providing the drums. (The Wersi drum kits for the Yamaha styles had not yet been finalised)
The computer spec on the 2005 demos was a 2.4GHz P4 and 1 gig of Ram.
The videos being from over a year later (Around June 2007) meant users were starting to get the hang of them, and the computer spec used was 1.5gig of Ram and a 3 GHz P4.
Its now 2008 and the yearly summerfest has now just passed, so hopefully some more demos will be posted soon.
The current instruments run on a Dual Core AMD CPU, however I am not sure on the amount of Ram used. (OAS 7 was updated late 2007/early 2008 to make full use of Multi Core CPUs)
The most common VSTs sold by Wersi dealers are Colossus, B4, (A specially modified version that uses the physical drawbars and controls on the keyboard, as well as full editing capabilities from within OAS) Virtual Guitarist and Real Guitar.
My favourites are Kontakt 3, True Pianos and believe it or not the free SGM180 Sound font. (Not cutting edge, but great in a mix)
Currently I am clearing the system out so as to upgrade to OAS 7, without needing to bother about the system being clogged up. (Although to be fair there has not been any problems since it was upgraded to XP in early 2002)
BTW the best demo is probably the 3rd one. (The first one should have included all 3 files, but for some reason 4 Shared didnt upload properly)
Cant wait to get OAS 7, however I am still undecided on the OAA (Coming from an organ background an all singing all dancing style section has never been a great priority) but will do an in depth trial at the September Pakefield keyboard Festival, and then make a decision.

English Riviera:
Live entertainment, Real Ale, Great Scenery, Great Beaches, why would anyone want to live anywhere else (I�m definitely staying put).