I thought the tone was spot-on, and it was a ton of fun. I was disappointed with how I had to just "roll with" some of the weaker elements of the story and tell myself that they didn't matter. For instance, the cookie-cutter evil villains with no motive or explanation. I also thought that maybe 80% of Deadpool's wisecracks landed, and the other 20% were trying too hard. Still, it was very very funny, genuinely surprising in places (the opening credits were genius), and I can't wait to see what's next.
I really hope they don't go too far and rush into an X-Force movie next. There needs to be another bridge crossed before then, IMO, but once the studio suits see the box office returns, they are going to froth at the mouth and demand the next Avengers. Idiots gonna idiot.