I am extremely lucky in that I find radiology intellectually stimulating. Even when I am busy, I appreciate that I am engaging my brain in a way that I find meaningful and thought provoking, even if I do feel exhausted when I get home. However, I also try to remember all of the things about other specialties that I don't miss - things that are easy to forget when you've been doing this for awhile. For example, I enjoy being able to eat, piss, sit down/stand up, drink, and scratch when I want to. I enjoy minimal and/or focused patient contact - the kind that permits me to easily move past the irrelevant story about the old woman's granddaughter, and I enjoy not having to round. Also, I enjoy knowing that my work is complete when I leave the hospital.
In general terms, radiology is just as flexible as other specialties. I know people who work 3 days a week, no weekend, no nights, no holidays. I know people who work overnight shifts exclusively, both 1 on/1 off and 1 on/2 off. I know academics who work 9-5, but at a slow pace, with opportunities/obligations to teach. And I know people who work traditional private practice jobs, with call and very heavy production requirements. Everything is a trade-off, and you need to be willing to sacrifice. Between pay, location, and lifestyle, you'll probably only get to select two, and maybe only one, particularly if that one happens to be location.
Specifically, radiology is mostly shift work, with the expectation that you will handle everything assigned to you between time X and Y. For example, I can leave at 5 pm, but typically only if my list is clean. If you're slow, then expect to stay later to meet production expectations, especially in private practice. Practices handle work distribution in myriad ways, but you don't want to be the person reading less than your peers, nor do you want to develop a reputation of dumping on your colleagues.