I use the European Hero because I travel overseas a lot, and fortunately it works on U.S. 3G networks. After using this thing the U.S. version is a travesty as it's one of the ugliest phone's Sprint has ever come out with.
However, If you're like me and you send out tons of e-mails, text messages, picture mails, all to multiple people, and use the internet a LOT, then nothing can compare to the ease of use of Sense UI. You'll never go back to another phone unless you have to (I have a Sprint Diamond that gets paid for by my work).
For you...correct me if I'm wrong but it sounds like you make a lot of phone calls more than anything else. If this is the case, then get the Diamond or Touch Pro 2 with sprint. If you're like me and you send out tons of e-mails, text messages, use the net etc....then get the Sprint Hero (though I must warn you, the phone is fugly).