You must differentiate between lifestyle in residency and after residency. In residency, from what I have read, radiology has better call schedules (q5-q15) depending on the program and the year. However, you must keep in mind that radiology residents at many programs stay up the whole night reading studies, doing ultrasounds, doing angios, etc. Although I'll admit I don't know as much about anesthesia residencies, they seem to be more often on call, but with more opportunity to sleep when there.
After residency, radiology in private practice is becoming more and more a 24hr specialty. Partners in a group often have to cover the hospital and will get consulted to read studies. This is being made easier with teleradiology, but is still a night of broken sleep. Academic radiologists for the most part do not get disturbed much when on call b/c the residents handle almost everything.
In terms of anesthesia attendings, I have heard that it is longer hours than in residency. Often they manage several patients and oversee residents and CRNAs. Again, someone else might offer better details on this topic.
So, all in all, I think radiology and anesthesia lifestyles are similar. Rads is changing and becoming harder, but at the same time is improving with telerads. There is, of course, the exception of interventional radiology, which is generally longer hours and you must come to the hospital. Although I can't specifically answer your question, I hope this info helps you decide.
Another thing to think about is what you enjoy doing. Rads and Anes. are much different. One is into diagnosis and figuring things out (and procedures in IR). Anesthesia is all about small procedures, physiology, and pain management. Think about what aspects excite you before you decide.