"You were recommended to me by my manager who took your class 5 years ago. The only way I can take 3 weeks long class if you were teaching that class."    ( Few weeks later: )  "Heinz, I got my number today. Thanks for the crazy weeks I spent with you."
CCIE 23044

"I highly recommend Heinz Ulm's CCIE preparation training. Heinz provides the finishing touches that one needs to be successful on the CCIE lab exam. Through his tutelage my skills were fine-tuned so that I was able to go into the lab without fear ( really, I was Uber-confident! ) and pass." 
CCIE 20503

"Thnx Heinz, You really are a special man, if I succeed, it will be especially of the way you have motivated me as a human being, sometimes the inner strength can make someone undefeatable.........."

"The class with Heinz was an outstanding experience, his exam hints and teaching technique made me very self-confident to take the exam right after the class."
CCIE 21033 on 1st attempt