If I were to pick out my favourite Flash rogue it would have to be The Mirror Master, not for any practical reason, more for the concept of the character and a fascinating gimmick. But on balance not many of his stories have satisfied my preferred vision for the character, his potential remains untapped.
Does anyone out there feels there is one particular story he was well served in...?
I just reread John's Flash run. I thought he did some great work with the Rogues and that Mirror Master had some great storylines. Johns really used the mirror gimmicks well. The run started off in a mirror world, MM was the one who kept the rogues in contact with one another and he was doing constant jailbreaks.