For context, we have the Sundance Optima, which is rated for 7 or 8. Usually, it's just the wife and I. Occasionally our two kids join. Several times a year we have 7 or 8. Even with just the two of us, it's nice to be able to changes seats. So for us, the larger tub was the right choice. There is a marginal extra cost however, since you will possibley pay more for the spa itself, some more chemical usage, extra water to keep heated, etc...