I have a completed comic that's roughly 500 pages that I split up into four books, and the biggest problem you run into when you have different volumes is stocking.
If I'm selling books at a convention, and I sell out of, say, book 2, I'm not going to be able to sell books 3 and 4. But the books don't sell evenly -- everyone needs book 1, but maybe half those people will also buy book 2, maybe only a couple people will buy book 3. I end up playing a balancing game with Books 2 and 3, since they're absolutely necessary and I don't want to run out, but they're also going to sell extremely slowly. If I have 5 copies left, do I reeeeally wanna buy a whole new batch, knowing I'm only gonna sell 2 or 3 at a time?
The more "middle" books you have, the more you run into this problem
One thing you can do to ponder printing it as one huge book would be to take an actual book in your home, and count out how many pages your comic would be, total, to get an idea of how physically hefty such a book would be, and whether it would feel like a solid book or just really unwieldy.
The last consideration is timing. Despite knowing about the "middle book" problem, I print my fantasy comic in 30-50 page issues... because that's how much I can do in a year. If I were to wait until I have a full 250 page volume completed, I wouldn't be able to print a book for five years, and since I do conventions that's a long time to wait! So, if you want to break it in two so that you can go ahead and publish the first half, say, then that would make sense to me also.
