I went to the Kaplan practice test at the college in my area the week before my first official administration. It was a very good experience for me and very different from the "proctored exams" I had given myself, thanks to the 50+ other people in the room.
Kaplan worked with the prelaw group on campus, so I just emailed them and they got me in touch with the campus rep. I emailed him to ask which prep test they were going to use because, as I informed him, there was a good chance I'd already taken it. He was super nice, emailed me back to say it was PT 57 (which I had taken) and said I was welcome to bring me own exam, which I did. The Kaplan people checking students in looked at me a little funny, but it wasn't a big deal. I just left when they did the "Kaplan strategies" portion.
Just because it may not be the best test prep company doesn't mean it can't be useful in some way.
ETA:
PattyCake wrote:The added 5th section alone will make it more realistic because I'm pretty sure Kaplan free test simulations only give you the 4 sections from that test, they don't actually test your endurance for the real scenario.
Nope, they do the full 5-sections. Actually, the administration I went to was exactly like the real thing, except the paper was a different color. It was even in the same room. The only difference was that people were chatting in the practice test and the room was dead silent for the real thing.