As part of my new deck planning I thought about an Endless Pool stand alone addition. Primarily looking at the smaller units that have a hot tub and swimming jets. It would sit off the deck on a concrete platform.
I'm primarily looking for arthritis relief and low impact exercise.

Zoning or permits may be a major issue in Chicago.

Any experiences with these units?

Don’t know much about them. I will say, hot tubs of some flavor seem to get more use, year round, than a pool.

The maintenance is easier, possibly zoning laws too.

I've dealt with 2, for clients.

Zoning shouldn't care, as long as the slab and utilities fit within your lot setbacks. But then I'm not familiar with Chicagos zoning Peccadillos.

One was all electric, the other had NG. Both were energy pigs, but if you're going to use it, it may be worth it to you. Go with NG, you'll still need power, but oi, all electric is only worth it with solar.

The install wasn't too bad, best if a flatbed with a crane can get where it needs to go.

Both clients could afford to have someone look after it... One client used it daily and had it heated year round.

I don't recall any major issues, but I think maintenance/operation are hidden costs. If you'll use the hell out of it, do it. If it's something like weekly or less... your wallet will tell you no.

Either a hot tub or a endless pool, those that try to combine the two do neither well. Swimming you want the water at around 84 deg, hot tub around 102 deg.