I'll have to agree with
@PapaBear on the Ditto if you just want a basic easy to use looper.
Having said that, there are just so many out there it's hard to say it's better then whatever the latest is.
There are some very interesting functions on some of the new loopers out there, I'd suggest you need to decide how you want to use it before you buy one.
Having said that, I believe one feature that you should ponder is, whether you want to be able to save and store loops and jam tracks on it.
Personally, I currently own two loopers, neither of which saves loops, I just don't need that function.
Others like that function and you might be disappointed if you're doesn't have that feature.
If you just want to practice your timing and have fun laying down your own rhythm loops to jam over, then something simple and realistically inexpensive like the Ditto will serve you well.