the boss rc series kills. if you're a beginner, i'd recommend the rc-1. it's very basic, but this is a good thing at first. you'll want to get yourself to the point where you can click it on and off in time with the music, making a multi-bar sequence that stays in time without any quantization. don't even worry about midi to begin with, just sync yourself up with your own playing. looping seamlessly is its own musical skill.

once you get to be more of a wizard, you'll want things like backwards playback and multitrack looping and midi sync. you could progress toward more advanced boss pedals, or start looking at things like the electroharmonix 95000 (i have one, i bought it because i saw a video of reggie watts using one)

it's always gonna be a tradeoff between simplicity and complexity, and honestly more complex isn't always better. i find myself reaching for the rc-1 way more than the ehx95000 because it's so simple. just experiment, figure out how YOU like to loop. there's no right or wrong way. the gear should make you want to keep playing. if it doesn't, trade it in for something else. don't burn too much time deciding.