Well, if your choice is between Navy and Marines, remember that the Navy uses 46s, too, and theirs are even older.
The 46 gets a bum rap a lot of the time. The Cobras look cool and shoot a lot; the 53s are huge, powerful, and fairly new; the Hueys, well the Hueys get the bad rep too, so I sympathize with them. Besides, they have to hang out with the Cobra types--no sense of humor, those guys!
It comes down to mission. The basic 46 mission, assault support, is really one of the best out there, if you're into the whole Marine thing. Inserting troops in the zone, on time. There's the classic vertical envelopment, but also the more exotic FAST roping, recon patrol inserts, para ops, SPIE rigs, etc, etc. Everyone else, including the Cobras, are flying above the action--you're flying right into it, with 2 aircrew manning .50 cals.
53s do assault support as well, of course. Their heavy-lift capabilities lend more to materiel support than troop lift. They especially do a lot of external lifts. I will say that their long range and excess power has made them one of the platforms of choice when it comes to long-range raids and inserts, such as the seizure of Camp Rhino in Afghanistan. At first, people doubted the 46's ability to operate in the high altitudes of Afghanistan, but once we were brought in, phrogs were a key part of the package, and excuted raids and logistics support in country.
If you're a lifer and know it, 46 squadrons are the base element that the air combat element (ACE) of the MEU is built around. That means that a CH-46 squadron CO is the leader of the aviation unit most likely to go in harm's way. That's not a bad deal, and a good way to end up a MEU CO eventually. Both of my MEU COs were former 46 squadron COs.
I believe the phrog mission can't be beat. It certainly beats the mission of any of the Navy helos, hunting for submarines and drilling circles in the sky waiting for someone to crash. My only concern is the future of the 46 with the recurring delays in the replacement program, the V-22. Now the 46 has to stick around to 2017 or perhaps longer. In the meantime, we're getting new engines and some assorted doo-dads, but they are all interim fixes. I'm love the phrog now, but I'm kind of worried about being on the "C team" if I'm still flying it come 2014 or so.
So, it's a mixed bag, but what in life isn't? There's nothing cooler than touching down at night, dropping the ramp, and having 15 Marines rush out. Everyone else out there is supporting YOU, because you are the main effort.
Phrogs phorever