I did a whole project on this back in the day so here's what I can say, although a few of these cities my info might be outdated.
Obviously NYC is the Mecca, but SoCal is pretty decent in this respect. Non union doesn't have near the trouble they do in Nyc getting seen at Union calls, BUT I've been told being Equity in this city in terms of work is hard because once again, everyone is skimping on Equity actors when legally possible to save money, and sometimes it is legit to keep a theater afloat. Also, maybe I'm missing something, but I don't see the big Broadway shows here auditioning over there, so I don't think this happens as often as people think. If they are, it must be secret or something. I know Telsey has an office out there, so I've seen a call or two for their shows, but I really haven't seen all that many others audition out there. The people I know who are based out there who have gotten some big tour gigs and even a Broadway show or two, I also know they have agents so...yeah. But that's my observation.
Chicago-Great regional city BUT it's still very much more of a straight theatre community than it is a musical theatre one. It's the biggest reason I've never even considered living there.
DC-Also great regional city, but many sources tell me it's incestuous to the extreme and to be aware that if you do live there, be prepared to be patient to get your career there started.
Orlando-Ok, I know someone who knows more is gonna have to add to this, but it's struck me as a city that has decent theatre but it's not called the theme park capital of the world for no reason. I don't think I need to remind everyone that the three biggest names in the theme park industry all have parks/resorts there. It's also struck me as more of city that better for dancers, and a few dancer friends of mine confirmed this to a few years ago, but if that's changed, someone feel free to say so. I'd considered moving there at one time, but when I'm a singer/singer who moves ok, combined with that fact that these theme parks are more dancer based and not a whole lot of singer positions compared to the **** ton of dancer positions, and not a whole lot of theatre itself to chew on (although those theaters are GREAT) I wasn't about to do that.
Philly-GREAT city. I have quite a few people I know who live there, one is Equity and she's seems to be doing just fine for herself there, but I also know there was some luck involved, BUT that one lucky streak has helped keep her employed. Another few aren't Equity, but some of them are still working pretty regularly. Philly itself is pretty great, but its also part of a larger community since you can easily-ish commute to Jersey, Maryland, and Delaware for the theaters there also, such as The Eagle, Candlelight, Compass Rose (if you can stomach it, I've heard be wary of this place), among a good few others.
Atlanta-This scene has really exploded in the last 5 or so years, and I have a friend who has been living off and on there and really hasn't stopped working completely. He's had to supplement himself with a day job for the lower paying theater ones, but I honestly don't recall the last time he wasn't doing a show with at most, a small break in between them. I did my theater city project on Atlanta back in the day, and it was pretty good then, but it's only gotten bigger and better since then.
Updated On: 9/25/17 at 12:21 PM