I bought a couple radios from Bell's in the past year (President Lincoln II and Magnum 357). No problems with Bell's at all, and good customer service.
I didn't have any modifications done to my radios, so they shipped pretty quick. I can't comment on tune ups or mods, but Bell's has a lot of videos on YT showing his work, and it seems reasonable.
I saw the RCI radios hit the streets. Have there been any changes made to them?