The Pre has a good foundation with some important features, but is coming up short in terms of applications and some of the finishing touches of it's existing features (like viewing a missed call!!! Missed Calls - a MISS). I am optimistic that with the power and presence (and promise!) of additional carriers, some of these 'features' will be fixed and there will be an incentive for developers to develop good (or even common) apps for the Pre.
Additionally, there have been numerous rants about what the iPhone's exclusivity with AT&T has done for the market. I think having the Pre available on multiple networks not only expands Palm's consumer base, but gives consumers more choices. More consumers, more choices and more competition will raise the bar for innovation and capability for this and all smart phones. Hopefully, things like battery life and viewing missed calls won't be sacrificed because of the 'niche' market created by the phone.