I've lived in NYC for about 20 years now, and I'm looking to move out in the next month or so. I "discovered" a couple of things on StreatEasy and in general that might be helpful, so I wanted to share.

I read through the wiki (awesome resource by the way, I got myself a copy as a checklist! Thanks!) but didn't find these things mentioned.

The building class is listed in StreatEasy, and can be helpful: it's somewhat hidden. You have to scroll down and look for the "About the building" link toward the bottom. It will take you to a similar page with a bit more info, rent history/prices, and such. Look for "Facts" over there; it's a collapsible menu. It will tell you what the building class is, and if you hover over the question mark to the right, it will tell you what it means.

This is useful to know if the building has an elevator, how many apartments/families are there, etc.

The website with the full key is here: https://www.nyc.gov/assets/finance/jump/hlpbldgcode.html

Check for complaints/violations: The DOB has a search index (currently at https://a810-bisweb.nyc.gov/bisweb/bispi00.jsp, but just Google it), and you can search by street address as well as other things. I don't think I've ever seen a single building without those, and the goal here is not to look for fewer complaints (though that's not bad either) but for patterns.

If you see a building that has several complaints about scaffolding being up for three years combined with complaints about drugs/syringes going three years back, you know this is a problem. Frequent complaints about garbage not being collected or spilling and rats, you know this is a problem. But if you see a single complaint about a significant leak two years ago, which was closed, and no other complaints (especially if the building is from around 1912 or something of the sort, which is not that uncommon) - that's normal.

Extra tip - look to see if those patterns are resolved and answered by something like "no evidence of (complaint here) when (police, firefighters, whatever) arrived." This means several people complained about the issue, and the city does jack shit about it, which is something that happens in some areas more than others (311 says the police came and found nothing, but actually no one came; just check my ventings and the responses of others who had the same issues).

(emphasis) - Talk to the neighbors and walk around at night: This is in the wiki, and it's good that it's there because please, please, do it. Do it more than once. Talk to different people. It's weird to walk up to a stranger and be like, "Hey, I wanna move here. What do you think?" but get over it and try. Be friendly and don't wait for them to answer to "excuse me" (because a typical New Yorker would think you want money), just show up with business casual clothes (for guys anyway, it looks "safer" I think) with papers maybe that you printed from the DOB or whatever, and ask your questions. Don't do it when you're with the agent. Do it alone at a different time.

Things like issues with pests, drugs, noise, garbage, and other things you may not even think about will come up. Talk to women if you can. Life in the city is still way more dangerous for women. They have a sixth sense for trouble, and they will tell you shit you wouldn't even consider. Decide what's important to you personally later. Of course, don't forget please and thank you.

I hope these are helpful in some way!