The first time i used it in 2015, we didn't get our request at POR. I used it this year at Pop and we got the third room away from our request, so i would consider that a success
I used TP room request for the first time last year and while I did initially get placed in the room I requested, someone was already in there when I checked in so we had to take a different room. Not Touring Plans fault, so yes - they try very hard to get you the room you want! Also, you get a discount when you subscribe if you can answer a few questions from their current Official Guide!