Well, I agree with most of that list with Mas, Ken and Leatham at the top.

IMO you can scratch Pincus off of that list.

A very good friend of mine and his girlfriend, attended one of Pincus' classes about 5 or so years ago in Milford CT. Early on in the pistol defense class, a "student/participant" came up to Pincus during a break and asked him about his own pistol's durability. Pincus asked to see the student's weapon which was unloaded (dry range portion of the class) and the student complied.
Pincus threw the pistol downrange onto the asphalt range about 20 yds., scraping and nicking up his finish/sights etc. He then told the student with an attitude; he could see how durable his firearm was. The student who was kind of a "Casper Milk-toast" type just stood there in shock. Several others saw this, including my friend and demanded they were leaving and wanted their money back. The female assistant who checked the participants in at the beginning of the class, tried to smooth it over and explained to them that Mr. Pincus was just a little "intense" but that they don't do refunds after a class has started. A few participants wondered if Pincus was "on something" as his behavior was really strange the entire course. My buddy was pissed about the situation but didn't want to lose two admission fees he had paid for and stayed for the duration. He was unsure if the student ever reconciled with Pincus after the class, but my friend said he would never go back to a Pincus instruction class again. It was really weird and unprofessional behavior.