2H: Right-hand dominant, but working on adding more ambidexterity. For F2L, I definitely use a good amount of left-hand during solves, but finger tricks aren't as smooth. They haven't been improving much recently, probably because I need to do more slow solves to solidify my left-handed finger tricks. For LL, I just recently began trying to relearn all my OLLs and PLLs in my left hand. I already have some of them down. I have two of the G-perms down left-handed (the ones that start with R2, or in this case, L2), which is actually proving VERY useful in some solves, even though I haven't perfected them. I haven't bothered with the other two since they wouldn't be quite as useful. I'm also learning to do F2LL left-handed... and right-handed for that matter. I don't know all the algorithms yet.
If anyone cares to know:
For OH, I use both hands, but my left-hand does a better job. I've always used my left hand, but I started using my right hand about half a year ago. It's improved a ton. I average 19-21 with left hand, and 25-30 with my right hand. (For right hand, I usually start around 25, then my hand gets tired, which results in 30-second solves...)
LH OH has actually helped my cubing overall in terms of equalizing hand strength. In terms of finger tricks, it's mainly helped with the right index finger push-back U' (finger moves from FRU to RUB), which I use for left-handed F-perms and a few other things.
What's really cool is when you find out how many little things you do unintentionally right-handed when learning to do LL algorithms left-handed. You don't even realize where your fingers are moving, which is why some algorithms fail the first several times left-handed, for example, [r U r'][R U R' U'][r U' r']. I was learning how to do this algorithms left-handed earlier today. I couldn't figure out what was going wrong until i compared it with my right-hand version. I kept trying to just tilt my fingertips back out of the way at first, but it turns out, I actually lift and move my fingers in the back completely out of the way of the middle layer in my right-handed version of the OLL, but I didn't even realize it at the time.... Idk, at least I thought it was pretty cool. Like, straight up, my left-hand is so ridiculously uncoordinated. It's so fascinating.