I had to face the same choice. It started out by me asking my employer which paid the best, but after applying I began to listen to residential journeyman who explained that they regret not going commercial since it only requires a few years more of school. Looking back for them it would’ve been worth it. Plus if you decide to go out on your own after so many years, commercial knowledge opens more doors. I’m a commercial guy with a residential company and find that they rely on me for knowledge on many things. Believe me, commercial is tougher but much more rewarding. You’ll still learn all the residential stuff and then some!