I get that you work with what you have (in this case, a corpus of job postings), but a ranking that places Baltimore in the top three tech hubs fails the sniff test. CBRE has a better list here (email registration wall): https://www.cbre.com/research-and-reports/Scoring-Tech-Talen... I'm biased in that it places Atlanta unusually high, but overall it is a better, less surprising ranking: Bay Area Seattle New York Was…
Atlanta is the center of tech ambitions for the southeast. It has a lot of Fortune 500 company headquarters - Turner Broadcasting with 18+ major online brands, Home Depot, Lowe's, etc. Yahoo and Google had offices. There are also a lot of small satellite consulting firms. Cost of housing is much lower, though traffic is bad as well. It's a nice green city, but Venture funding is low, so it depends on your ambitions.
That includes those fortune 500 companies (a couple of whom had internal recruiters bail when I mentioned my current salary + the COLA number). Cutting your real estate costs by $12-15k goes a long way but it doesn't magically cover $40k+ paycuts. It is good for employers (for instance, one guy was willing to disclose "I got two guys with Master degrees for $20k less than what you wanted.") but not so good for employees on the upper end of the pay scale. (i.e. above 6 figures outside of SF/NYC)
It is anecdotal, just my experience after looking to move there.