> -I have a .ca adress. Will it change to .com
Nope, it won't change.
> -It gives me the new features faster (right) but does it do something
That should be the only visible change for you.
> -Are there any disadvaantages to this
Depends on how you look at it. Since you get builds earlier, it does mean that they haven't necessarily gone through a full soak with the users yet. So if we have any new bugs, you'll be more likely to experience them. On the other hand, when we have new features and new fixes, you'll be among the first to experience those.