Hi, Mark:

Dive in, the water's fine.

As Jaap suggested, the free trial version will let you find out if Composer is for you without risk.

I use Composer every single on projects ranging from fully-orchestrated musicals to one-off songs and there has not been a project yet where it let me down.

The learning curve is not steep. Once you have a keyboard connected, recording and editing is very intuitive.

And it still has, to my mind, the best midi-to-notation interpretation engine around, bar none.

David