Honestly, I have no perspective, having never been in a 6x6 before and usually avoiding being on the water in general. The only thing I was basing it on was reading articles that said it would go between 6-10mph (and that without the jet they would do 2-3). I really don't know how fast I was going, and probably never went straight long enough to get up to top speed anyway.
I was glad to see that it worked well and I could easily use both the jet and the wheels at the same time.