Why an uninstaller? I recall some distribution sites will not allow apps to be listed unless they include an uninstaller.

Contextual menus? Command or Control click for the trial and error approach. (This works better for Mac users, who really don't read user manuals anyway) Hmmm--looks like the user manual is back up again-- http://www.limewire.com/english/content/userguide.shtml

Menus? For OSX I use the default OSX theme (View), which put the menus in the menu bar, not the window header.

Pro/vs free? I haven't seen a discernable difference: There used to be no difference, other than the ads. Perhaps as more people upgrade such differences will become more appparent.

Pro/Basic Verifying? The only difference I've noted is with OS 9 and OSX. OSX verifies very quickly, OS 9 is very slow.

I'm having trouble separating your questions into 'expert user' and 'programmer', so sorry if I guessed wrong. Just another Mac user.

Cheers