I guess they are alright. I came from the HTC Eris. It's capacitive buttons were a pain. You had to press toward the top of the icon, not directly on the icon. And even when you hit the sweet spot, occationally there was no responce. I tried the HTC Incredible in stores and thought the capacitive buttons were a dream compaired the the Eris.
All that being said, I bought the Droid X unseen. Knowing I wouldn't have the problems I had with the Eris but wouldn't have the experience the Inc owners have.
The Droid X buttons do take some pressure to activate. Nothing extream, but the fact that they are so thin, the tip of my index finger hurts slightly when I use the keys repeatedly over a period of time. I'm a big guy, so I have big fingers. That may be the reason for the irritation.
The irritation goes away quickly after a phone browsing session. And I haven't and don't expect to develope a callus on the tip of my index finger. Above all, take this from my post. Even with this slight irritation, I love my Droid X. Without a doubt it's the best phone I've ever owned.