Like others have already said, FG-X is very coloured (and people who disagree need to update their monitoring chain!!). Pro-L is definitely the smarter "go-to" option of these two. Until then though that's all the help I can give! Good luck!
Apparently Slate are working on an FG-X 2.0 which is a whole new design from the ground up, so this will likely resolve all the problems I mentioned above which would make it a beast of a plugin. From what I understand the FG-X was designed to make "healthy" masters (RMS -8 to -10) so it makes sense that pushing it too hard might result in distortion as it was not designed for this, that said I have experienced distortion before reaching -8.Īll in all, I can only speak for FG-X but even though it may not be the cleanest limiter of all time what it does do it does very well I think. What I love about FG-X is the ability to hear the pre and post limiting levels at the exact same volume so you can hear clearly what effect your limiting is having and then using the built in controls you can 'restore' the sound of dynamics and punch back into your mix, most of the time I can even make it sound slightly more punchy post limiting which is really cool, especially cool how easily you can do this too. That said, in your question you mentioned "clean" and I have quite a few times now experienced distortion with FG-X when I push it too hard, but sometimes I need to push it that hard so it's letting me down I guess. FG-X has received a lot of positive feedback from industry pros and I use it all the time, almost always during mastering.
I don't know about FG-X 'coloring' the sound, I wouldn't say it does that noticeably, or if it does it certainly isn't bad sounding.