HTC One Newbie - Do's, Don'ts, Definitely's?

Hey fellas!

After my iPhone 5 slipped out of my pocket at the same time as I was slamming my car door, I was left with a bent phone and a tough choice - get a new iPhone or try something new. I was never going to go for a Samsung (because, well, I like phones that feel good) so I am now a proud owner of an HTC One in black. The nice lady at Three kindly let me pay off the few months of my contract left and sign up to another 2-year dealio (which I'm fine with - Three are awesome).

I just have a few questions and I'm sorry if there's some crossover with other threads...

- I hear there's already a way to revert it back to stock and get rid of Sense. Is this worth doing and what are the drawbacks?

- I've downloaded the majority of apps I've been using on my iPhone and the stock Google keyboard, but other than that I'm pretty much stumped on badass shit to get on there. Any tips?

- What's the best way to sync with the music on my mac? I heard DoubleTwist was good?

- My contacts is a mess with all the FB, Twitter and Google contacts. How do you all organise your contacts?

Any other advice would be super appreciated. I want to really give Android a go, but if I can't get along with it I guess I could sell it and go back to iOS. But you wouldn't want that, would you? ;D

Thanks guys!!