I've also been using this since it came out, and it has made a noticeable difference. My game was already fairly well running , but the mod has certainly made an improvement in CAS, particularly with pattern loading.
I haven't observed any noticeable temperature increase maybe two or three degrees if that, but I am also paranoid about cooling so I have a lot of fans, and my GPU and CPU temps sit at about 35° with this mod running in my game.
I also have some anomaly problems with Sims 3 but not related to transitioning back to the main menu; mine is on shutdown of the game, ever since I installed Win 10 on my new PC. On my old win 7 machine the game would shut down immediately, but I have to sit staring at a black screen for anything up to 1 minute when I try to close the game on my win 10 machine. I don't know what causes it though and it doesn't seem to be related to the length of time playing the game either. It still does it whether the game has been loaded for 2 minutes or two hours ( not really related to the mod, but I mention it in case anyone might know why this might be happening )