Should I take this AM job? - Fairly large AM

Hey everyone, I was hoping to get some opinions on a job opportunity that has presented itself.

My background: 2-3 years in sell-side equity research in a regional office. Comp is solid ($120-125K all-in) and work-life balance is nice, but I want to go to the buy-side.

The job opportunity is with a fairly large AM firm ($50BB+ AUM), but it is an entry-level position. The comp is basically the same as what I am making now, maybe even a bit less, and my cost of living would go up as the firm is located in a major city (one of NY/SF/Boston). The position is designed to transition into a full-fledged equity analyst role in 2-3 years, and my recruiter said most hires are making around $500K 5 years out.

The opportunity is generally what I am looking for, but the biggest drawbacks are comp and location. I'm not sure if I should take a "promotion" to the buy-side if it comes with an effective decrease in comp, and I am wondering if I should wait for a better offer (but of course that better offer may never come). I also have become used to living in a mid-sized city where my money goes a lot farther than it would in a major city.

Any input would be appreciated.