3/1 or a 4 bedroom one and a half

[John DarrenKamp]

I have a 3 bedroom 1 bath home with a full unfinished basement. I am looking for some advice on finishing the basement and adding 4th bedroom and a half bath. There's not enough ceiling clearance to get a shower in the basement. The question I feel that needs to be answered is there a drawback for only having a 3/1? If so how much? Other items of interest: if I leave it as a 3/1 i will be able to rent it out and make roughly 200 net on the property. If I add the finished basement the rent that I could collect would no longer cover the mortgage and expenses. I like to have at least two exit strategies (renting or selling) however i would like opinions on 3/1 versus 4/ one and a half. 

Thanks -John