I have had a hot tub for 5years and a spa for 15 and we decided it would be our family fun and that it has been. Kids learned to hold their breath in the hot tub I would bring my scuba cyclinder and two regulators and they would be under for 20 minutes at a time. Hot tubs are deeper and more of a bigger vessel spas are where you lay down more and get under the water that way. Jets 20 ,30, 40 it dose'nt much mater if they are not pointed at you. We have a foot well a big plus for just a big jet on your feet or anywhere else. ours is a great lakes brand and has run well for 15 years , not flawlessly but well. Inside I would think about that, a friend rented one for a party put in the garage thinking it would be cold other wise the sheet rock fell off the ceiling with all the moisture (there is a lot of moisture )and you can't see the stars. We are in ours just about nightly and last night it was -22 ° and with a hat on perfect. With young kids under 100 lbs keep the water around 98 ° 99 ° any hotter you cook them like a hot dog , not enough mass .Ours runs about $75.00 a month to heat and run I keep the pump on all the time to prevent freezing and we don't run it in the summer. They are a bit of work to maintain but I think it's worth it they are fun.