704set,
Although I agree with yokeman that Nordic is a good product there is no comparison in the two lines, that would be like comparing a golf cart to a hummer!
The Arena is an incredible spa and one of the oldest designs out there. That model started from the old round Grecian spa that was sold as an in ground over 25 years ago. Great product, great massage, fantastic sanitation and overall one of my favorites!
As far as service of a "built in spa", most importantly you need to leave a removable panel or cover near the equipment bay to get in and work on it. Remember, someday you will be paying someone by the hour to do maintenance and the easier you make it on them the easier they'll make it on your checkbook!
Try that Arena out with a wet test and you will see what I mean!