Tax liens appear to be simplistic from the surface but are very risky for beginners. 

All things are rarely equal, though, and that is a very simplistic answer to a very complex question that has a lot to do with you, your situation, the deal, etc, etc.

I have tried the interface and it's functional; simplistic (read: easy to use), not a lot of bells nor whistles which is good if you're trying to bring up the grading curve in certain areas where cash/money orders/ mail payments are still the primary methods.

Simplistically, the model is develop, build, rent, sell - with the formula being:Sale value - costs = profits (if you are long term hold then: cash flow / equity = return on costs)So often we see folks get in love with their projects, then start to lose site of the "gut check", keep gut checking at every level, every step if you can, keep your model/proforma open, and update each time you get a new data point on rent, costs, etc.Ann and Weston have the advantage of having done it before, so they likely have some general sense of sale values when a small apartment project is complete, and Ann for sure has the costs dialed in.

Obviously every situation is different, but if your question was pretty simplistic (ex "Hey, if i sell X property for $XXX, what's my gain?")

I actually found a good one that is a little more simplistic.

However, even then it only provides you a simplistic metric that must be combined with other metrics for decision making. 

It certainly can be a good resource, but to quote our instructor "this course is like drinking water from a fire hose".For the pricetag, it was well worth it for me and I intend on taking the other CCIM courses over the next 18 months, but as a principal, you need to weigh the usefulness between paying for this course, and learning the information here on BP.  95% of the time, you can get away with using a more simplistic model to analyze investment deals for your own use. 

Critics believe his advice is too simplistic. 

It's fast, and really simplistic.