Yep...it is good to play in other keys rather than one or two favorites, although sometimes a singer's vocal range makes that decision for them.

Soloing in unfamiliar keys can be a bit exciting, but I wouldn't go on stage without at least a few rehearsals in the new signature.

For Rock and Roll and a lot of Pop Tunes, I find the keys of A and E work equally as nice for pounding out a piano lick as well as soloing with an organ or other sustaining type voice...but that's just my preference.

One thing for sure, in the early days, with Hammonds, Rhodes, DX-7's and MiniMoogs, you didn't have the luxury of transpose buttons so you played in the agreed upon key, and made the best of it. One could say, it was certainly never dull.

I do have to say, the tranposer has certainly made some potentially difficult situations much easier, so I'm a supporter for sure.

Ian