Even for OH CFOP is probably the most popular method. In general it's a good choice to use the same method for 3x3 and OH (no matter which), because you mutually train both events by doing only one at a time.I use the CFOP method and I have been using it for OH solving. What is the easiest/most popular method for OH solving?
Also, I average about 1:15 and what is a reasonable goal that most people reach easily?
In general CFOP, ZZ and Roux are all fine for OH solving. Roux has the advantage of being almost rotationless (and of course movecount), whereas it can be tricky to learn M slices with table abuse. I don't know much about ZZ but it seems like the main difference regarding OH solving between ZZ and CFOP are z rotations vs y rotations. The former is easier to execute. However, no matter which of those is used, the cuber wants to make sure edges are oriented when reaching the last layer, then LL algs are all great.
When I started training OH casually I reached times between 30 and 40 seconds pretty easily without excessive training or learning special OH algs.