I've been using the RC3G for a couple years myself, and picked up the Hobby King version back when it was on sale for under $30 as well. Last night my GT3C just came in.
My plan is to convert all of my RCs to work with the RC3G, all of my son's RCs to work with the HK version, and all of my daughter's RCs to work with the hacked GT3C. Not only will this significantly cut down on the number of controllers banging around, but it'll give me some good experience comparing the Radiolink radios to the Flysky. Should be fun.
Last night my quick impressions of the GT3C were that it's a comfortable radio, and feels better built than the radiolinks. My biggest complaint with the Radiolinks was that they always felt like the plastic was paper thin and not really well molded. I also like the rechargeable battery in the Flysky. What I don't like about the Flysky is that the 3rd channel button and trim button are in a position that accidental activation seems like it could be a problem, especially when my 5 year old is using it. Time will tell.