I've been toying with the idea of getting a swim spa for the last twelve months.
I first looked at in ground pools with a swim jet and heat pump however this was going to be in the $70-100K range. Swim spas tend to fall between $25-70K, with the amount of water being pumped for the swim current, how smooth the flow is and the pool length determining the price.
They tend to range through 3 jets, 5 jets, then the endless propulsion system with a smooth water flow.
They all seem to have spa seats and massage jets however the problem I see is that you would want it at a lower temperature for swimming compared to sitting in a spa, so ideally the swim spa would only be for swimming, with a separate spa for sitting. We are heading down this route and have bought a new spa pool for under $5000, and will look purely at the swim functionality of the swim spa. We haven't had a test swim yet but I think it will come down to whether the water current produced is fast enough for our swimming speed (relatively slowly!), and the amount of turbulence produced by the jets.

Any pool (be it an in-ground pool or swim spa) will have significant running costs and maintenance requirements. When I became the executor of my parents' estate, I spent many hours over the summer keeping the in-ground pool clean and sparkly while the house was on the market. I was well and truly over it by the time the house sold...

I suspect maintenance on a swim spa would be far less onerous purely for the fact that most of them have covers like spa pools which fully seal out the weather, leaves, tree debris etc.

Having said that, $70k would buy you an awful lot of annual passes at the local community/council pool. If it were me, I'd be making damn sure that my family and I were definitely going to use it every single day ad infinitum. Otherwise, it's a lot of money to have depreciating in the back yard.

The other thing to look at is opportunity cost. Assuming you are paying cash for the pool but still have a mortgage, that $70k would do a lot more good for you in the long term if it were used to pay down your home loan and save on interest costs. Even if you were planning to finance the pool, I'd suggest that is only a good idea if you have already paid your home loan off in full. I never borrow money for depreciating assets - that's the number 1 rule from my book 'How Not To Be The Working Poor 101'*

I go swimming a handful of times each year - this year I have so far swum at Lake Benmore (Dec to Feb), as well as Maui and Waikiki (a few weeks ago). Whilst I did pay $800 airfares to Hawaii, the actual swimming cost me nothing. And I saw some big as turtles lol.

*I haven't actually written a book