Which East Coast City to Live In?

I'm very familiar with philly - you've gotta be careful because the safety of an area can change extremely abruptly from area to area. If you want to get a good sense of pricing in a few different but reasonably safe areas I would look in these neighborhoods: Graduate Hospital, Manayunk, Passyunk, Fishtown. 

Philly is cheap because it’s a god awful city

Philly/DC are great places.

I'm going to throw you a curveball and say you should check out Baltimore given your interest in Philly.

Baltimore is a great place if you are looking to stay connected to the NE corridor. Baltimore has great museums, culture and authentic people. Its a sleeper city due to negative public perception of the city from the Wire. Given recent trends in capital flow it appears that it is attracting many people from Philly and DC due to the urban infrastructure/amenities as well as the affordable/historic housing stock.

Fuck, I typed out a fairly lengthy reply but WSO ate my comment.  

TLDR Philly perspective:  can get a decent place in Rittenhouse/Fitler Square which would be my first choice of neighborhoods, followed by Washington Square West / Society Hill / Old City, where you can get a bit more house but worse schools, and maybe parts of Fairmount and South Philly (Grad Hospital, Bella Vista, East Passyunk) although to me there is limited appeal living outside of Center City.  From living there before, you know you'll be paying the highest local tax (~4% gross) in the country.  City faces a rough recovery in the post-COVID world as it is far from the economic powerhouses of NY/SF, and is generally unfriendly to businesses.  Critical mayoral race is coming up to replace the current abysmal mayor, and there is a non-zero chance of a total lunatic winning who has the potential to be even worse.

Still my hometown though.  Go birds and fuck the celtics.   

Philly! It’s cheap and affordable vs nyc

All are good places but I'd personally only go for NYC or Philly, especially if a lot of your friends are in NYC.  No point listing out all the pros/cons since it will be an endless debate and its ultimately a personal decision. 

If I were in your shoes, I think the decision would pretty much come down to:

If you can handle the COL and the high energy (and often stressful) vibe of NYC, go NYC (and maybe try southern BK or Jersey City or something).

If you want something much cheaper and more laid back, but still with like 80% of the big city amenities NYC has and is a short trip to NYC itself, go Philly. 

I think it depends what you're after and your age. Do you want to go out / are you single? Are you in your 20s, 30s? For this discussion, I'm assuming you're single, and in late 20s / early 30s. 

I live in Philly right now (Rittenhouse Sq. area) and reverse commute out to the Main Line. Prior, I lived in NYC for 4 years, and before that, Boston (North End). 

I would not buy in Philly. Compared to the other cities, it simply doesn't offer everything it should for what you pay. As someone else mentioned, you get killed with the 4% city tax; the crime (while not as bad as the news makes it out to be) is definitely a consideration (along with the homeless); public transit is dirty and unreliable, and everything closes extremely early (I was on a date at a speakeasy on a Thursday night and was told it was last call at 9:45pm - wtf?). Lastly, the traffic and drivers are horrible. 76 during rush hour is a parking lot with people illegally taking the shoulder because the cops don't do anything; and everyone now has a car after COVID shut down public transit. Lastly, if you're going to have a car, good luck finding parking (unless you have a garage in your building). I'd say my happiness and quality of life here is definitely the lowest compared to the other places I've lived. I'm looking at buying on the Main Line , $1M - $1.2M is doable for a nice small place in a decent area; but again it depends what you want (traveling into the city from Main Line is a hassle, and the airport can be a ~1 hour drive). That being said, I have friends who live on the Main Line and they rarely (if ever) go into the city. 

Boston was fun; but it is small, and expensive. The layout is impossible to drive in (the city transit / T system breaks down a lot, and it's slow). That being said, its clean and safe. The winters are something to take into account - few feet of snow are possible. (I guess that doesn't matter if you're WFH though). The parks are beautiful, and you're close to the NH White Mountains / VT if you ski / snowboard. But... you have to deal with Boston fans. Potential tradeoff. An alternative would be to find a place right over the line in NH (no income / sales tax) which will save you a considerable amount of $.

I'd recommend NYC over Boston / Philly (however given you want to buy, that might make things difficult). The food, the night life, the public transit. Everything just... works. You're surrounded by smart, motivated people. And if you do buy, you likely won't lose money. 

Someone recommended Baltimore - I have been there quite a few times (inner harbor area) and I 100% would agree it's worth a look. It is clean, new, there are a ton of breweries and cool things to do for someone in their 20s / 30s, and you can raise a family if you want; so something to look into (and Fells Point might be in your price range). 

The only one not on the list is Richmond (which I've heard generally good things about), but unfortunately I do not have many details to share. 

Pittsburgh is pretty underrated. 

NYC, Miami, Charleston 

Spent about 6 years of my life in Philly. Very under-ranked city! You'll have a blast if you go there!

If you want to be near-ish to NYC but get a little more space for your dollar, why not just do what all the MDs do and live in Stamford or Westchester or something