The main thing, with hemming knits, is keeping enough ease and stretch so that the hem doesn’t ‘pop’ when being worn or put on and off.
I have a cover-stitch machine (which is great when it works). Before that, I used to neaten the raw edge with a zig zag, turn press and then stitch with a large stitch (3.5) stretching in the fabric a bit as I sewed. It could be a bit wobbly but would usually settle with a good steamy press.
If you have an over locker, another great method with plenty of stretch, its press your hem, them fold it up, right side to right side, and over lock the raw edge with the bottom fold of the top.
When you press is back down you will have a neat self band with plenty of give.
I have not used a rolled hem foot but maybe someone else has?
Not to blow my own horn, but have you looked in the tutorials section of the Oliver + S blog? With just a bit of tinkering and practice, you can get a great, professional looking, and nearly unbustable hem using a twin needle.
A simple zig zag stitch will work well too, and if your thread colour matches well is not that bad to look at.
@eboyd83 Emily a serger and an overlocker are the same thing, just US vs Aus/English terminology.
A coverstitch is the separate function which looks like straight stitching on top and serging/overlocking underneath. A coverstitch can be a stand alone machine or a combo serger/coverstitch.