We have the Bissel SpotBot for pets as well, and it has worked wonderfully. But... The stains we've used it for are cat puke, not urine.
The thing with urine is it gets deeper than the SpotBot can take care of, so the SpotBot might get the visual stains, but you won't get rid of what went down into the padding. That can encourage the dog to use it again (or other animals to go there in the future.)
I echo Kajem on the Nature's Miracle - the key to it is following the instructions to completely wet the area and let it dry on its own.
For any surface stains after you've done that, the SpotBot would probably be a great choice.