I've been to games in Buffalo and Toronto, both at their old arena's and their new ones. But I haven't been in a while, I've seemed to have lucked out as I've seen some pretty cool stuff happen at the few games I've been to, one Buffalo game Alexander Mogilny had a natural hat trick vs. the Islanders. The only game I went to at the new Toronto arena Yanick Perrault of all players became the first leaf in a decade or so to score four goals in a game, and another game I went to at Maple Leaf gardens the Leafs utterly destroyed the Hawks.
The old arena's had more atmosphere and more core fans, though the newer ones are obviously much better facilities. Seeing a game in Toronto is difficult just de to the high demand for tickets and they are in a price range that is nowhere even close to what I'm willing to buy. Haven't been over to Buffalo for a while now either, I used to be able to get over their with just my drivers license but now you have to have a passport and I haven't bothered renewing mine. I'm not as much a fan of Hockey as when I was ten years ago either so it's not very high on my priority list.
OHL games can be pretty fun, the arena's are small, tickets are cheap and it's an intimate atmosphere, on the opposite spectrum are AHL games which are pretty dire, the arena's look half empty most of the time and TV coverage is very limited, I've been to some Hamilton Bulldogs games but it's not that great.