Were you talking about me? I only lived in Ballston Spa for two years and I'm not a native. However, I'm in the real estate business and we pay attention to potential investments.
What I mean by "bad" street is a street that I consider a street that has lot's of rentals, especially rentals that are not well maintained. Probably a good spot if you are looking for a cheap place to rent and looking to bum a pack of smokes from your neighbor now and then in exchange for watching their pitbull. Those neighborhoods are concentrated around South Street, North High Street, Ralph Street, Bath Street...basically areas close to the river that have that classic run down mill community vibe. However, streets like McMaster and McLean have some of the most amazing Victorians in the area.
There's a remarkable amount of renovation going on in some of those areas right now though. I can think of three projects just on South street off the top of my head that popped up recently. With the Malta factory and finding just the right spot, Ballston Spa might be a good investment. 3 new and nice places to eat opened up in the past year or so downtown so that tells you what direction the community is headed.
There are a couple of nice B&Bs in town and I think they are both on the south end of town. I have no idea how busy the existing B&Bs are though. I imagine they try to cash in on the Saratoga craze but I'm not sure if it keeps them going year around.
Ballston Spa is not dangerous or crime ridden. Our neighbor did have a 2 gallon gas tank stolen by some kids though...