@Starlilly88 agree totally that every school has good and bad points, which usually depends on who you are, your own perspectives, experiences or expectations. As someone who knows (very well) a number of people who think Tormead is a great school for their DD, yet also have their mini-moans now and again, I can understand that you will have heard different things. For context, this forum alone is riddled with good and bad points about St.Cats, GHS, RGS, Lanesborough, Cranmore, St Teresa's, Etc etc......!
I guess what I have heard from friends, and a number of other posters have alluded to, is that the new head master at TM seems to believe in a community where parent (and perhaps more importantly student) viewpoints are encouraged and listened to. I guess realistically every issue can't be solved for everyone, however mums I know say there has been a real evolution at TM, and are pleased with the direction of travel.
Speaking from personal (although not current) and a number of second hand experiences, it's a great school, with the some of the best teachers in the area..... although don't get me wrong, you wont be hard done by for generally great teachers at any of the Guildford independent schools!
Good luck and don't worry too much about the little pros & cons, think more about where you think your DD will fit in, be relaxed, make friends and have an enjoyable education. Academic wise, there isn't much to differentiate the three, apart from GHS pulling ahead of the pack. If you DD is motivated she'll get good results at any of the Guildford schools.