I had Apple replace my hard disk (under AppleCare) but they left two microscopic pieces of dust behind the glass. I could have brought it back to them but rather than spend an entire day driving back and forth to the Apple Store I decided to fix it myself.
Removing the glass is super easy with the Heavy-Duty Suction Cups. I had a helper ready to hold the patient down but you could probably remove the glass without help.
Reassembling an iMac while keeping dust out from behind the glass is very difficult. I used a can of compressed air but the dust just wanted to settle somewhere else. If you want to do this routinely I suggest shaving your head and the use of Tyvek jumpsuits. Maybe convert that unused bedroom to a "clean room" for Mac repair too. No home should be without one!