I really like both radios, I use my RDS800 as my carry radio. I have it in the van with a couple of electrics in case a flying field jumps in front of me. The SD-10G I use for my Giant Scale gas planes. The throttle curve is one reason, stick switches are another, they really can reduce workload in certain situations.
I Agree with all of the above posts, I too started with an RDS8000, then moved up to the SD10G.. love it, I still have alot of learning to do, as far as programming goes, but otherwise love both transmitters..