Sub vs Carrier

My son is still at boot camp then off to Nuke school. He is considering signing up for sub duty preferring to be "on/off 3 months" at a time vs carrier "6 months on/off". He is engaged (to a wonderful young lady that we all love) and will be married by the time he graduates nuke school. Of course they want to be able to see and communicate with each other more often. Are there any resources you can suggest, that can shed light on the sub vs carrier? Specifically;

1. Are there any videos that might show life on each?
2. Are there any members who know sailors that served on both?
3. My son has also mentioned higher pay on a sub...any idea what the difference is?

I want them to have as much info as possible before they make this decision. My concern is that before leaving for boot camp my son stated that he could not imagine being "cooped up" on a sub, not being able to see the light of day, smell fresh air, etc, and we all agreed. Now that they have been apart 2 months, they are thinking that being apart 3 months vs 6 seems more tolerable. I am sure there's more to the decision than the time and pay difference. Thank you for any input. Mark, Longview, TX + A&M '82!