Probably the worst piece of advice I ever heard given was to a student whose QXC route took her through the Shawbury CMATZ twice. She was told that she need not bother to talk to Shawbury, strictly true but an incredibly stupid piece of advice given the area through which she would be flying. For those who don't know, Shawbury is a very busy CMATZ (busier than a certain apparently anti-GA airport not a million miles away) which handles both a very large amount of Military Air Traffic in their local AIAA and civilian traffic. It is also the Military ATCO School. The ATCOs at EGOS are, in my experience, always unfailingly polite, patient and very helpful and a real pleasure to deal with. I know some people have a bit of a hang-up about talking to Mil ATCOs but it is an unfounded fear. I would always talk to a MIL ATCO, probably in preference to a civilian one as I know I will be treated courteously and not simply have "Remain clear of controlled airspace" barked at me, that is if I manage to get a reply other than "I'll get back to you" (that last was before I had even been asked to "Pass your message").
So, if you are near to a MATZ talk to them, you will probably be very pleasantly surprised by the way you are dealt with.