system
Given the following post, respond as if you're commenting on Reddit:
human
Is a "luxury" high rise building being built across the street good for my properties value?

Ok, so I own a shitty condo in a middle class neighborhood. Couple of weeks ago a developer announced they were making a very nice building in front of my apartment, were there used to be a vacant lot.

It feels like this would have positive externalities on my propertys value, but doesn't this also increase the supply for living space, lowering my propertys value?
gpt
There are too many factors to consider to adequately answer your question. 

It's quite possible that, in the long run, it'll be good for your condo because the area generally improving will make your unit inherently more attractive to buyers. (More money coming in, more businesses, etc.) 

But it's also possible, if there is enough undeveloped land, that more and more new condos are developed which would make it harder for you to sell unless you did major renovations to compete with what's being offered.

So, it's too tough to say. There are a ton of factors that go into real estate speculation. As a very general guess... If you live in a really dense area, then I'd bet you're value will go up. If you live in a sparse area, then I'd bet your value would go down.