Update: I've had the bike for five days now. I like it even better now then when I first got it. I can understand the concern about "outgrowing" the bike, though. It would be a luxury to have a little extra power in reserve at highway speeds (70-80 mph), but just typing that it sounds a bit ridiculous. I just know that when I'm up around 70 on the highway I can tell I'm near the end of my power band. There's a bit more, mind you, but the revs are pretty high.
That said, I think the M50 is close to an ideal bike for a beginning rider - as long as you've taken your MSF course (and passed). It's very easy to ride and a heck of a lot of fun. I know a lot of people here will say don't bother with a new bike, but I'm sure glad I did.
One last thing: On the power issue - I weigh 200 lbs even. I'm guessing you don't weigh that much; in which case any possible power issue is that much more irrelevant for you.
Get the bike. You will not regret it.