Benelli M4 or M2 Tactical?

[SubSolar]

I was looking to buy another semiauto shottie in case they get banned by the Obammunists. This one would be strictly for self defense so I wouldn't really need to use light loads. I am looking at the Benelli M4 or M2 Tactical because I don't have a Benelli yet and have heard great things about them. Here are the advantages I see for each one after researching:

M2 Tactical
About a pound lighter (6.75 lbs vs 7.75 lbs)
Greater capacity (5+1 vs 4+1)
Cheaper by at least $400 (some places $600)
Comfortech stock option
Inertia operated system can stay cleaner and easier to field strip


M4
More reliable if you add accessories like lights
Gas operated system can shoot lighter loads
Marines use it (possibly more rugged?)
Less recoil (although I'm not sure if you get the M2 with Comfortech)
Looks better

It seems like the M4 in black is a hot item and sold out at most places. Also the prices at gunbroker and some shops have gone from about $1550 to over $1800 now. Meanwhile the M2 Tactical can be found everywhere and the one I want is about $1150 (Comfortech stock and non-ghost ring sites). Am I missing something here? It seems like the M2 holds it's own with it being lighter, cheaper and holding an extra round. Many say the inertia system is cleaner and easier to field strip too. Is the big price premium for the M4 because the Marines use it?

 

[Medusa]

I don't know much about shotties, but I've understood the inertia-system gives out more recoil, while the gas system tames it considerably. Also, the ARGO gas system on the M4 is reportedly a pretty clean system, which is a huge plus for a combat shotgun (USMC).

Sadly the M4 is more expensive. But if you're looking for a semi-automatic shotgun for SH/HD, why not consider the Saiga 12 too? that should be a lot cheaper.

I'm not personally a huge fan of the shotguns (have shot one Mossberg 590 only once), but if I'd buy one, it would be a Saiga 12K or Benelli M4.