Bullfrog, d1, and hot spring are top tier manufacturers and are among the best options available. I would not put vita in the same class from a quality, energery efficiency, reliability, factory support, or therapy perspective. You can get a large sized spa like that from D1. The Amore Bay and Serena Bay are in that same oversized class.
Honestly, the largest Bullfrog and Hot Spring models are more than enough for the vast majority of people. You may be different, but I've found that most people who think they need a spa that size end up later realizing that the never have that many people that are all ready to go, in their swim suit, and get in the spa at the exact same time. Typically, someone is sitting on the patio furniture while someone else is still changing, and then another person is getting out because they are overheated, etc. Most 2nd time buyers are downsizing. First time buyers ten to go bigger than necessary.
Again, I'm only speaking in generalizations and your situation may vary, but I wouldn't pick Vita over the other reputable brands just because of capacity. imo, of course.