I haven't had any experience with the round vs. square teeth thing. However, the first time I had my timing belt changed, I took it to a hole in the wall operation. I brought OEM Honda belts to them to use; but the first time I went to picked up my car from them, it was making all kinds of squealing noises, etc. As it turns out it was related to how they had mounted the belt. I had to take it back and have them redo it.

Let the dealer do timing belt jobs and use OEM parts. Generally, the dealer refuses to use anything else so it's just a better deal all the way around.