I haven't used the ones that came with the 650. I had some old, literally, Fellowes (is that how you spell it?) screen protectors from my Vx. I cut it to size and it works great. I've had no reduction in clarity or brilliance.
I have the Vaja and the screen protector. Managed to drop the Vaja with the Treo in it.
but, the Treo came out like a champ.
And, the Vaja fits the Treo much better than the other hard leather case at the Treo store (sorry Chris). I really think the Vaja is worth the price.
Hunter