Got my DX3S Yesterday, it's quite an impressive product. It does everything I need it to do, and more. The DX3R won't keep me from crashing, or driving better, but it did come with an extra receiver (about $90 to buy one otherwise) and cost $70 less than the R (So I saved $160!). I had a chance to feel both controllers in person, and prefer the feel of the S model. I have big hands, and like the option of changing grip sizes!
I was skeptical about the telemetry options, but it ships with all the sensors, and they are all light weight. I only hooked up the electric motor temperature sensor, which is pretty trick.
Overall, I'm very impressed with the DX3S. Now I need to get a 4WD, so I can use that extra receiver!