I hear they want to charge an addition 10 bucks a month on data, for those with 4G phones.
Breaking: HTC EVO 4G available June 4th for $199.99 « Boy Genius Report
Of course you should also consider the availability of 4G in your area.
Looks like a sweet phone, I am curious as how good battery life will be on it however.
A 70 dollar data plan on the phone is a bit much in my opinion...