I think a plain edge is more versatile. It can be sharpened fine enough to shave with or you can edge it with a coarse stone and put a micro-serration edge on it to cut ropes.

Serrated blades require a bit more work/time to sharpen and this can't done with a simple flat stone. I have a Spyderco tri-angle which can make this a lot easier to do but I never really got the knack of doing it on my Spyderco Delica.

Personally I prefer just a simple fine edge the full length of the blade and that's the only type of blade I use now except for the separate serrated blade on my multi-tool. YMMV. I don't cut enough rope to make any significant difference or need for a serrated blade.