i am also interested in this topic mainly since im thinking about choosing cardiac vs other anesthesia specialties.. heres what i think so far as a new ca1
cardiology: you have to endure internal medicine residency (painful), you have to do well and match into cardiology (want to move across the country?), then you can do EP or interventional, both are good, or do general office cardiology stuff. i think its too much thinking about not enough doing, and when you do get a chance to do procedures its the same exact thing over and over.. caths, ep studies, echo reads..caths are bad ass but otherwise kinda boring
cardiac anesthesia: your an anesthesiologist, you are kind of bad ass in the sense that you can handle anything, code expert, airway expert if someone crashes, less geeky more getting the job done, hand arrythmias, do TEEs routinely which is cool and cardiologists dont normally do (TTEs primarily), and you have an END point with the patients, get them through surgery, period, with cardiology you are fighting off the inevitable most of the time
however, the anesthesia cardiac docs seem (in general) like the more TYpe A, high-strung residents in general in my experience (though limited)