All of them are a workout! I've rented both, I like the Ryan's a bit better. I'd really like to try a reciprocating but have yet to see one for rent.

If I knew for sure that I had no big rocks buried in my lawn, I'd want a Toro ProCore 648 but that's pure fantasy! Most places that rent them will not rent to homeowners.

 

Any ride on aerator you can rent will be easier on you than any walk behind. The second choice would be a walk behind that has a hydro transmission that has two triggers a left and a right so you can turn it with engine power. Some of these have sulkeys/velkeys to ride on. (see The Stinger line)

 

I rented a bluebird aerator from my local Ace hardware that worked well. It's a walk behind so it was a workout but it worked.

 

I've used the Classen and the Ryan. The Ryan is nicer as the tines spin independently and allow for easier turning and it has add on weights.