sell house and invest equity or keep as rental?

I would say it depends on where it's located, how much money you can get in rent, how much your mortgage is, whether or not you need the money from selling it, how much attention you can pay to your tenets, ect.

I have a house that I use as a rental and it goes both ways. Can you fix things or do you know someone that can? You need to make sure to keep extra money available if something breaks (i.e. A/C, washer/dryer, roof). If you can get enough to make the mortgage payment and put a little aside for stuff that breaks then you are doing okay. Just remember you need to do work on the house every other tenant or so (or every 1 to 2 years to keep it up to date) or else it will get too expensive to fix in the future.

But remember once it's paid off there are not too many other investments that will pay you $1,500 per month (obviously with some headaches) You are also building equity qith each mortgage payment they are making and you can use that as a line of credit in the future.