If you're concerned about the S not being fast enough, don't worry about it; it's fast.
Mostly it depends what you're looking for and what you want to do with it. I love my S for the week+ that I've owned it and now that we have access to the PS Store I'm even more excited. The screen is perfect, resolution is great, sensitivity is good, design and feel are also pretty good. I don't like that it's difficult to incorporate an SDCard cause they want you to use internal storage or whatever, but it's not a big deal. I'm certainly never frustrated with performance.
I'm also fairly certain that this'll get an Ice Cream Sandwich update soon after it's available, so I'm pretty happy with the longevity potential with the tablet S.