The RTT is a nice unit, albeit a little pricey. They justify the price because you can adjust on the fly, but I have had both the GPR sub mount on my 04 YZ450, and on my 06 I have the Scotts.
In actuality once you get used to it and find the magic setting for you and your style, you pretty much set it and leave it. Also one downside to the RTT is that it is likely to not be transferable to your next bike. Unless nothing has changed with the frame, tree, and forks. In which case why did you buy a newer same bike? I run my Scotts 7 clicks out and it is perfect for everything. I ride mostly Desert, Enduro's, and a little MX track, and don't ever have to change it. The GPR was nice but did raise the bars too much, and their customer service was not the best. They sent the wrong parts twice, and would not send the right ones until they recieved them back both times. Wasted 2 1/2 weeks of my ride time. Scotts on the other hand was great to deal with. Some people may find it hard to spend the $400 or so on a stabilizer, but I have been saved from some would be ugly crashes out in the Dez too many times because of it. I will never own another bike without one.