What are some online websites/ software platforms for RE portfolio managing?

Maybe it's a long game -- offer him a 2 or 3 year lease with discounted rent along the lines of his current PITI.

Honestly man most of those companies, they make more money then they do on there real estate portfolios, and they use on online platform and you have a "coach" who has very basic knowledge. 

I need some advice on online rent payment collection services.

How long have you been in the fix and flip game?

I purchased BiggerPockets Pro so that I could do the analysis of properties I have found online and with the help of a real estate broker, and I even made my first unsuccessful offer to puchase a property.

During the football game last night it took me about the entire game (just a little less).

Once I feel I have an appropriate rent price, I require all of my prospective tenants to complete an application through an online credit check & tenant application website.  

Its an online community similar to Bigger Pockets, but the topics are on all types of investments/finance (rather than just RE) and it's specifically geared towards towards doctors. 

We are sitting on 19 units right now and yes the headaches will drive some people out of the game.