I personally have never been impressed by any online demo from any manufacture, (Artists performances Yes, but instrument sounds and styles Ho Hum) in fact if I went by online demos I wouldn’t have bought any.
This is the reason I always listen to them and play them live before making a decision. (I also go to many Live music venues to re-acclimatize myself with real sounds, so as to make accurate comparisons (I never compare artificially produced sounds with other artificially produced sounds, unless the original sound is artificial that is)
As an example:
When purchasing my last keyboard I made sure that I tried as many different types as possible, (Again comparing with Real sounds) these included Yamaha, Ketron, Roland, Korg and Bohm, and out of all of them I was pretty much set on Roland, (Sound,, Interface and feel were brilliant, and would have kept me happy for many years) however following my advice (Even though the Demo CD and Video were not exactly inspiring, I stuck to my guns) I made the 420 mile round trip to try the Wersi, (OAS 4 at the time) and boy am I glad I did, as for me, it quite simply left the others high and dry, And this is why I now own the Abacus. (Upgraded to OAS 6 with a move to OAS 7 in the near future)
As new instruments come out I may find one that overtakes the Wersi, and I will probably then move on, however for the time being, for me, none of the others come close to the Wersi.

To sum up, my golden rules are:

1. Ignore Online Demos

2. Go to plenty of Live music events (Of all types)

3. Listen and play the instruments live (The way you interact with the instrument is just as important as to how it sounds)

4. Then and Only then make a decision (These are not cheap items, so take your time)

Bill