I have the PTPA too. Size small. I love it. He still has accident's from time to time, but I would guess that could be expected from time to time with any method of potty training. I love it, Bentley took to it right away. I keep an extra pee pad on the floor in my bedroom just in case he thinks he can't make it down the hall. 9 times out of 10 he stops playing and run past the pad in my bedroom and right into his PTPA and does his business.
Just last week I added a porta yard to it. Got one at Petco instead of the PTPA one.