Pretty flexible as a part timer (from what I can tell). I'm still waiting to be trained, so take that for what it's worth, but from what I can tell, part timers at my unit just tell the unit when they can work and are slotted in appropriately. Guys on orders have an office day/training day every other week to catch up on paperwork/training items and are not required to drill. Not sure when the part timers accomplish those items.

If by quality of life, you mean getting paid and never having to deploy... I'd say it's pretty high. Beware of boredom is what I'm hearing...