I am a CHQ-er, as are a few other members on here. I've been there a while so I can't give current information on the interview process, other than to tell you it was fair and reasonable. A "wunderlick" personality test that you can't study for, a written test based on instrument flying, then the HR/tech combo interview. Sim check on a PCATD emulating a BE-58. I was offered the job the next day by phone and in class two weeks later, but the timeline depends on the demands of the moment. Right now this looks like a good place to be, but we all know how quickly today's winner becomes tomorrow's loser. (Not that I have any reason to think that will happen here right now, but in this industry it's best not to enumerate one's fowl before their time.)
Definitely check out aviationinterviews.com for current gouge on the process. And if you have company-specific questions, post them and I'll try to address them.