Hey Zoo:
I think that to an extent, 2-speed pumps are hold-overs from the days before circ pumps. My 1999 Piper Glen has a 2-speed on one circuit, but I never use the lower setting. On top of that, the lower speed setting is REALLY low, not like half power or anything like that. For the most part, it’s useless (at least for me).
As far as using all the jets, it's all up to personal preference. Some days I like a hard massage with lots of water action. Other times, I just sit in hot water and talk on the phone. The advantage of having a lot of features is the OPTION of choice on the days you want it. A low-power tub without numerous jets won't give you the same experience. Some "custom" jet features particular to certain manufacturers also add value. You should try them and see if they "do it" for you.
One thing that was important to me when I bought a tub was that I could sit 4 people comfortably with each person enjoying hydrotherapy at the SAME time. If this is important to you, be careful when "wet testing" smaller, lower power tubs. Make certain that each seat can offer a good experience SIMULTANEOUSLY, instead of the diverter valve being used to direct all water to one seat at one time.
Good luck!
Drewski