For the first several months that I had my EVO, I didn't try any launchers (quite frankly, because I didn't know what the heck they were...coming from a WinMO phone, that concept was a little foreign to me).
I first tried Launcher Pro.  First thing I liked about it was that it had the scrollable dock that can fit up to 15 apps (if you use the maximum 3 scrollable docks w/ 5 apps on each).  2nd thing I like a lot was that it enabled the phone to go into landscape mode, while scrolling through the different homescreens.  I wasn't too in need of having to pay to get the "extra" stuff, like the widgets, so I just kept switching between LP and HTC Sense UI.
Then, all of a sudden, the more apps I downloaded, Sense UI became REALLY laggy.  I compared it to when I'd use LP and it was like day and night.  LP, although still had a little lag, was nowhere near as laggy as Sense UI was.  After debating for a week or so, I finally decided to go ahead and support fede and pay for LP+.
Now that I've been using LP+ for a couple months exclusively, I can't see myself going back to using Sense UI (unless they make it more customizable as well, not just widgets).  I'm a BIG fan of being able to see my entire wallpaper while scrolling through the different homescreens.  Whether it's transparent icons, the transparent scrollable dock, etc...LP+ was just perfect for me.  I like the "Sense-like" widgets, but I do have to agree with one person that said that the Sense UI widgets were slightly better.  
Nontheless, the FRIENDS widget is probably the only thing I have to complain about.  For whatever reason, even though I have it linked to the FriendStream app, it will not ever update my Twitter account whenever I post a thought.  I don't know if this is a LP (or LP+) issue, but even when I open the FriendStream app directly and try to post in there, my Twitter account still doesn't update w/ my post.  Maybe somebody that reads the LP forums more often knows the solution? - EDIT- Nevermind about this last tidbit.  After searching through the forums, I realized that somehow the twitter feed was unchecked to be updated.  Fixed that and all is well!
LP+ FTW.