I see some people use comps or other methods.

http://www.biggerpockets.com/forums/30/topics/105344-lonnie-deals---then-and-now---the-original-method-wont-work

. - I believe that some of the issues you posted elsewhere can arise after somebody has used the method shown in the second link of my earlier post.

As far as their reputation goes – it's a young market, it sounds to me a little bit farfetched that the can claim that they have "better" methods then the rest of the industry.

Your points on DIL are well made, and I've used a variety of methods to paper the file when trying to obtain DIL's, including extremely well written (pro-lender) Pre-negotiation letters.

There is a method called snowballing.

It would be a little disappointing to not get anything from using a method that seems to help other people land at least 1 deal a month from 160 letters while I'm sending out 300.

An appraiser would calculate their value based on what they call the "income method".Rents historically have also increased at roughly the rate of inflation.

Willing to explore any methods.

As @Brandon Turner mentioned the podcasts are amazing, and it will also give you a flavor to the many different methods you can invest in, for example this week @Ankit Duggal had an INCREDIBLE podcast on RE tax lien investing - was eye opening (at least it was for me).