Any Major Rule Differences?

Not really. They don't have touch icing if you are used to that. There is a delay of game penalty for shooting the puck out in your own zone and you need to be more careful about that because the glass is usually lower. They penalize fighting hard. If you drop your gloves you are gone and usually suspended a game. Not a whole lot of difference in the rules but there is in how they call them. The linesmen love to call off-side and icing and will call it if it is even close. The refs are very sensitive about anyone talking to them and will give you a 10 minute misconduct for nothing so try to keep your mouth shut. And I've seen a lot of really hard but totally clean hits get penalized just because they were so hard. It seems like they think if it was that hard of a hit it must have been dirty. But in general, like anywhere else, the higher level of hockey the better the reffing is.