If you get a job with an academic department, you'll get paid on par with the other faculty that do OR work. You may even get more money since academic departments are hurting for CCM faculty. The ICU requirement for residents is going up from 2 months to 6 months, and it is required that the residents are trained in units covered by Anesthesia CCM attendings at least 50% of the time. The demand for anesthesia trained CCM people in academics is only going to increase.
Private practice is a different story. Most intensivist jobs (not working in OR at all) that I have seen are offering about half of what you can make as a starting Anesthesiologist in the OR. However, I have seen groups that take turns in the unit and OR in order to spread out the cost of doing ICU work. The ICU work keeps your general medicine skills sharp, helps your relationship with your surgeons, and is interesting. If you can share the call and the decrease in revenue that comes with spending time out of the OR with several partners, critical care isn't a bad choice.