If you're planning to eventually go from single families to MFs, then go with a web-based property mgmt software that will scale with your growth.

but even so, I'd love to find something that's either web-based or compatible with the Mac system.

Lots of us have good primers on our web sites.  

@Sean OToole, On the Propert Radar web version, there is an export option Wise Agent. 

I am interested in participating in like discussions and/or web conferences from afar (being in Spain, it'd be a fair stretch to attend meetups in NY).

You should be able to find tax info on the appraisal districts web site.  

From web designs, to app development for property management companies, you name it!

Currently we have six conventional mortgage slots taken, so we are hoping to add a new property each year for the next four years and then our primary should be paid off giving us another slot. 

Hi Eugene, I found a previous discussion here: https://www.biggerpockets.com/forums/49/topics/165...Soundcu shows a limit of 90% LTV on their web site.

Lastly, I use a web based software called Joist.