You will find all kinds of opinions on the benefits and drawbacks of full foam insulation vs. perimeter insulation. There is one guy on here who is pretty adamant that you should not get full foam. Most however, believe the insulation should not be the deciding factor in the tub you choose. The arguments I heard when we were looking for our tub were that yes, it is easier to repair a leak if you don't have the full foam, but the full foam helps prevent leaks in that it helps prevent vibrations.
I don't have a whole lot of experience with hot tubs, but I tend to agree with those that say the insulation should not be the deciding factor in getting a tub. To me, the three most important things in the purchase of a tub are first of all to go with a tub manufacturer that has been around for a while and has a good, solid reputation for making a reputable product. Second, make sure you buy from a dealer you are comfortable with and you think is going to stand behind the product. And third, and certainly not least, is to wet test and make sure you are comfortable with the tub.
There are a lot of other things to consider like whether or not you want a lounge, energy use, etc., etc. but again, to me the most important things are the ones I listed above.
Good luck with your search and let us know how you make out.