NO NEED TO LOOK ELSEWHERE
I have had a driver's license for many years in my home country, but finally had to take the plunge and become "official" in the CR. After speaking to other expats and taking in the reviews with a grain of salt, I contacted Petr. He was very prompt in responding, extremely helpful along the way, as accommodating schedule-wise as any busy professional can be, and, most importantly, he helped to put me at ease with the never-ending Czech bureaucracy.
Like anything else in life, you get out of something what you put into it. While there are not many good English-language resources out there, all the test questions are online and are freely available for practice. Petr has a team of extremely talented interpreters who sit the exam with you and take all the stress and worry out of ANY possible language barrier issues.
Other than the fact that Czech law is ridiculous and requires experienced drivers to pay for a course (no fault of Petr's), my entire experience with Petr Sim was positive and painless.
One bit of advice - if you are busy and do not have a flexible schedule, just ask Petr to confirm your lesson with you the night before so everyone is on the same page and there is no miscommunication. That said, he always kept his word and our appointments.