Depending on which Fox damper you have Factory, Performance or Evolution they could be comparable or the Fox could be better.
The RL is Rock Shox’s basic damper, you have rebound adjust and low speed compression adjustment to lockout.
If you have a basic CTD damper (ie non-adjust) then you have rebound adjustment and a three level low speed compression adjustment, open, mid, lockout. The factory damper will add CTD-adjust (5 levels of compression in trail mode) and the FIT damper.
The RL is comparable with performance and evolution versions while I’d say the factory is better.
If you are happy with the way Fox perform (some people didn’t like the characteristics of older fox forks) I’d just service them, lower leg service is easy to do your self and there are loads of guides and videos on the web.
If you want to upgrade the damping as Mojo to see if you can get the new RC2 damper fitted in your forks. This is the same damper as in the highly regarded new float 36s.