Hmm..if you want more detailed opinions, I think you should provide what exactly you use the phone for on a daily bases. Then we can assist by telling you what it is and isn't capable of and how well it does it. Each of our uses varies.
For example, I spend a lot of time tethering and on my Epic 4g I tethered 24/7 for over 30 days at one point without being disconnected or shutting it off once. On my TP2 I get disconnected around once or twice a day so even that alone makes me much more happier.
Personally though, I am not a fan of sense ui..I didn't mind the interface of it on my TP2 but on both Android and Winmo its very bloated. So even if you get an HTC device, I would suggest getting rid of sense and try a custom UI or stock UI.
Speaking of UIs, if you want another UI that you might be very familiar with on winmo..there is SPB Mobile shell for Android.
SPB Shell 3D Brings Next Generation UI to Android Users » Press Releases » SPB Software
And to to your question, Epic 4g is latest kb phone atm..(there are leaks of newer ones but we haven't seen them land just yet and no telling if sprint will get them) The Epic Touch 4G is a touchscreen only phone but is 4.5" in size so it gives you extra real estate.
As for your brother, I am guessing he has a Moment? if so that phone is a low end phone..you can't compare low end phones with high end ones...
Also, how much of a hurry are you to swap? I mean by when do you feel you need to make the decision and get a new phone by?