We've been doing our weekly AL D&D for the last 6 months now virtually, as well as numerous cons. My results thus far:
Roll20 sheet creation is by far the easiest if you have to do it by hand. The site is very bare bones but it gets the job done and was easy to pick up. I'd only been back into D&D for a few months before we had to switch to it, and it went quite smooth. Plenty of character storage for free. All in all there's only a few things about it I don't like and they're minor. There are plugins to hook it into D&D Beyond so you don't even need to put in the sheet.
Fantasy Grounds does some very nice stuff in terms of tracking eg. Bless/Bane/etc. and concentration rolls, all the sorts of things you easily miss in roll20. But frankly I found the UI to be...very unintuitive and not user friendly. Character creation was confusing and complex by-hand but on the plus side you can import XML from eg. D&D Beyond, which by-passes that competetly.
I've only used these in an AL context so I can't speak to XP, but I use D&D Beyond for all my character sheet management in that regard. (We're in a shared campaign and so have most of the books available as a group.) So my recommendation is for roll20, with the warning that FG might be better for some people, I just found out difficult to use, where as roll20 is less polished looking but overall quite obvious in how to use it.