When I switched from my Samsung SPH-i500 to the Treo 755p, I was worried about how I would like the keyboard and I thought I would miss Grafitti, but I never had a problem. I had downloaded the Grafitti Anywhere program, but I never bothered to install it -- even though I was a pro with Grafitti, the keyboard was much faster, even initially. There's a small learning curve on how to use the function key to get to the special characters like @ and $, etc., but you pick it up pretty fast.

I remember reading somewhere in a forum a discussion of the Centro's keyboard and how it compares to the keyboard on the 755. If I remember correctly, the consensus was the rubbery surface on the Centro (and Pre) keyboard, makes up for its slightly smaller size. If you have really big fingers, it might be an issue, but I also seem to remember someone saying they just use their fingernails since the rubbery keys are so sticky, they get better precision and they don't slide off the key.