They have a great support team and their interface is very user friendly.

Can someone recommend some helpful but user-friendly software that will help me calculate the important financial metrics (e.g., leveraged IRR, unleveraged IRR, cash on cash, etc.) that I would need to know in buying small apartment properties (15 units at a time, for example).

They also have a mobile app that is very user friendly.  

The end user would lose money if deadlines were not hit.

That would help in determining the quality of the deal.Given my knowledge of Los Angeles and the areas that would command ~$1M for a duplex, your baseline rents seem on the lower end, especially if you are going to put in ~$25K in to each unit.

I joined their MLS in hopes that it would help but I've found it's not as user-friendly as Austin's.

On Podcast #17, Jeff Brown mentions that the "traditional" vehicles towards retirement wealth are dated and end up disappointing their users at the age of 60+.

I remembered the user who owns his own contracting business. 

I hope you're making the shift due to preferences and not desperation and frustration.If the latter, the issue(s) may very well be be the way you market and a fubdamental understanding of markets, segments, niches and how to reach them.Really, I'm not trying yo insult your intelligence; merely raise awareness of the potential to unlock the real business that you are in...marketing and satisfying customers (whether called clients, consumers, users or patients). 

I feel as the rental market in areas such as Medford, Malden, Somerville, Woburn, Stoneham, Wakefield, Melrose area's will command a much higher rental rate, and attract a higher caliber tenant.