>I think osu is fine, it's easier to set up especially if you already play in it, bad thing is you may not be able to tell what difficulties to play if you're not familiar with the files because of the awful star rating, though id say it's good for some casual playing
>o2jam is painful to set up, the engine is different so some charts do play better in it, though really I think most people only play it for nostalgia, mostly good for noodles. personally I think it's easier to just play the converts in this case
>BMS you can use Lunatic Rave 2 or Beatoraja, not hard to set up and there's guides, though may take a bit. both are quite customizable and there's difficulty tables that you can download so you can play things you know are around your level, they also support higher key modes if you fancy that (LR2 works better if you've a bad pc)
I think bms is your best option if you want to get better at rice faster, there's some noodle charts as well but it's mostly for the rice p