It's been a few years since I have gone through the selection process for a new Radio System, but here are some of my notes which helped me make a selection a while back:
https://www.rcgroups.com/forums/show...em-is-the-Best

I currently race with a Graupner X-8E and I am very pleased with it, main reason I chose Graupner was cost for extra Rx's were only $25 after Tower discounts. Dasmikro has since released some aftermarket compatible Rx's for Futaba and Sanwa which make those 2 brands more appealing to me now. If I were to buy a new system for myself today, these are the 3 brands that I would personally choose from. Main requirement for me is selecting a system that has steering speed adjustment, I would pass on any system without this feature.

For a budget system, I have had really good luck with Radiolink, I keep that system as a backup. It offers virtually the same fast lap times and consistency as any other high end system that I have raced with, but lacks many ergos. The guy that sold me his X-8E had switched to Sanwa and he told me that he missed the feel of Graupner where Graupner tends to work better for folks with large hands. He said the steering response feels better with Graupner, but throttle response feels better with Sanwa, but he felt that steering was more important than throttle.

I had traded up from a X-8N to the X-8E and precision you get from the X-8E is better than its predecessor.