I'm from Buffalo and I did my volunteer work with several OTs that went to D'Youville. The general consensus as far as debt was that they borrowed from $80k - $86k to attend D'Youville for the 3 years after all tuition, taxes, fees, supplies, and any other living expenses that they needed help with was said and done. While being able to work roughly 20 hours a week with their course load.
D'Youville is a 3 year program and it sounds like you would finish UB's program in 4 years. One year isn't a lot to add on when you're talking about that type of price difference. I got my bachelor's degree from UB and I absolutely loved the school. The campus is huge which I love and I had a really good experience. I'm not sure which campus OT is based on but UB's main campus is in Amherst which is a very safe town and the campus is like it's own little city. You can get practically anything you could want right on campus. D'Youville is in downtown Buffalo and it's pretty ghetto. You would definitely get more personal attention at D'Youville though since it is so small.