The music community is really tightly knit. I'm known in two different areas. I think more people know me (or of me) than I know of them. There are some differences between the two cities though:

City 1:
I've lived here longer, so I know most people and/or they know me.
Since they've known me longer, I have a less positive reputation with some of them.
I know people who own/work at the music store.
I have no way to start a composition studio as I'm not "known" as a composer here.
I'm known as a mariachi trumpet player, so I'd always have a job playing in one of those (however, that's not nearly enough to live off of).
This is the city where my parents live and being so close to them will make it difficult to live my life (i.e. I can't date, I can't start the band I want to eventually, and I would feel very pressured to move back home).
I could teach trumpet lessons, but there are a lot of trumpet teachers in this town despite its smaller population.

City 2:
I do know people here and am well known enough that occasionally strangers know who I am. But since I've only been here a couple of years, I don't know everyone. I do have connections with an important organization, with professors at the big state college, and to members of the nearby major symphony.
I only have a positive reputation here.
I personally know the people that own or work in the music stores, especially the one I'm looking at. Another store that I talked to a couple of years ago wasn't interested at that time, but I haven't asked again yet.
I'm known as a composer here and I also will get students directed to me if I start a composition studio, where I could make $40-60 an hour. Of course, I would never have more than a few hours a week doing this, but still.
I'm not known as just a mariachi trumpet player, so I'm not limited to just that one style.
There's a much larger population, so a larger market for both lessons and bands to play with/gigs etc.
This is the city where my parents DON'T live. So I would have the freedom to actually be myself, especially if I start making my own money (one way or another).
I could teach trumpet lessons especially since there doesn't seem to be a lot of teachers (proportional to the population) or at least they're difficult to find. If I had a place outside of a music store to start a studio, I would, but right now I don't. And being a studio teacher isn't the end result I'm going for anyway (unless it's a job on the side).
If I live here though, I've leaving my old mariachi band behind and that's what's been making this decision difficult...I feel really badly about leaving as they haven't been able to replace me in the last two years (I've been in graduate school). Also, this would mean if I want to keep playing mariachi, I most likely will have to start my own group in this city...possibly, but could be difficult.

So yeah, everything points to City 2, except that I don't know the owners of the music stores personally and I'd have to leave my old band (which I can't make a living doing that by itself anyway).

I have trouble going out of my way to meet new people, but I don't have problems if the people are there in front of me.