Questions about army and marines?

Just wondering why is that you see more Marines get out after one enlistment then any other branch? Also why is that a lot of Marines leave and go to the Army? I am asking these questions because I am getting out of the Navy in 5 months because the Navy is downsizing. They told me to get out or switch jobs and the only choices were submarines (no thank you). I had always wanted to be a Marine, but couldn't drop the weight at the time. I'm within Marine standards now, but I am afraid I have little knowledge on my questions. Is it because a lot of Marines are not approved for re-enlistment or does it suck that bad. I understand the hardship of deployments because I am on one right now in the Middle East for a 16 months. I am an E-4 and I know that I would have to start as an E-2, but I think I can make rank quick I would hope. I scored a 73 on the ASVAB and I have ociates Degree (30 credits shy of my Bachelors) so I am looking into the officer side. Also I don't know if my time will count towards high year tenure. If so I'll have to make E-5 in four years. I am also looking into Army because I hear they pretty much do the same job as the Marines and they have better facilities and are more family friendly. If anyone with experience could let me know especially those who have switch from Marines to Army or the other way around. Thanks