I may be missing one, but from what I gathered these are the big 3 headsets in the tactical headset world. Can anybody tell me:

1) Do all of these fit under a ACH (full shell/2000 cut)
2) Do all 3 of these amplify ambient noises and cut out high level noise?

There seems to be a lot of information on the web, but normally it comes down to "buy X because that is what I have"

Are these prices about the going rate:
1)Peltor  Comtac II:          $370
2)Peltor  Comtac III:         $500
3)Sordin  Supreme ProX: $360

When I watch reviews on them it seems like people get these for incredible prices, but I'm not seeing them.

Are there any other headsets I should consider? Anything I get has to fit under an ACH.

Yes to both.

I have both ComTac IIs and Sordins, and have used both under a standard TC2000 cut ACH, and my next set will probably be a set of ComTac IIIs.

Personally, I prefer the Peltors under a helmet when used with the head band - the way the Sordins' headband is designed it pinches my head making them less comfortable than the Peltors.  The Peltors are also a little bit more modular.  

Off the top of my head, the biggest differences between the ComTac IIs and IIIs are the fact that the IIIs use AAAs versus AAs, and the shape of the earcups has been slightly changed to fit a little bit better under the ear "flaps" of the ACH.

The NRR has also been increased from 20 to 21 in the ComTac IIIs (the Sordins are rated at 18) along with a variety of small detail changes, and overall "hardening" compared to the IIs.  

Are you seeking a comms capable headset, or just looking for active electronic hearing protection?

~Augee

Comms capable. Right now Anything I use makes it hard for me to hear ambient noises. I want to be able to hear with them on.

What are you using now?  

As I've mentioned, all of your listed options will do both of the things you requested.

Personally, I was issued Peltors, and used MSAs in a vehicle mounted configuration, so I picked up a pair of Sordins based on what seemed like a lot of recommendations that people preferred them to the Peltors as well as them being more durable.  

After using the Sordins, while I like 'em, particularly for wearing with a soft cap, the headband both pinches my head to the point where no matter how much "better" they were on paper, I prefer the Peltors to them, and the sliding plastic just "feels" a little brittle to me.  

That being said - in terms of them being more durable... I could be convinced of it, the last time I went to use my Peltors, I found that the boom mic had crapped out, which forced me to go back to the Sordins.  However, I just got a replacement boom mic for my Peltors which I was able to "plug and play" into my old set, and while I haven't tested it yet with a radio, it was a simple parts swap - if something went wrong with my Sordins, I don't know how if at all I'd be able to fix them without sending them out.  

If I was starting over, I would probably go straight to the ComTac IIIs over the IIs I have, and am in fact actively trying to trade my Sordins for ComTac IIIs, not just because they're an improved model over the IIs, but also because I'm looking for a dual radio headset over my current single comms models - but, take that for what it's worth.  

Once again, your head might not (is probably not) shaped exactly the same as mine, and you may not have any problems at all with the Sordins.  

~Augee

I currently just have a sound tube with an in-ear bud. I want to step up to something more professional.

It sounds like I should go with the sordins. You use the headstrap when you use your helmet? Is that pretty comfortable? Would it be worth getting ops-core rails and mounting your headset to that?

The IIIs sound like they are nice, but the price is a little more than I can swallow. What would you consider a good deal?

Augee-

What would you recommend for use with a civilian radio, I was going to just use a push to talk on an external mic and plug into the headset

That depends on what kind of civvi radio you are planning to use.

Peltor makes PTT switches that will interface with quite a few radios like 2-pin Kenwoods, Motorola XTS series, and ICOM radios.

I use the ICOM F3S handie-talkies, the PTT isn't as pricey as the others.  

It works fine with my ComTac III's.

SRS Tactical will have what you need after you choose a radio.

Guys on here have modified PTT's to work with Sordins and ComTacs, but that seems like a complicated affair.

I've never used any of them with any kind of civilian radio, so I'd probably be the wrong person to ask about that, but as Maintain stated, there are a lot of guys who've found/made solutions to work with civilian radios that seem to work that may have some input.  

All of my sets are "over the head" bands with the factory covers (cloth woodland on the Sordins, leather on the Peltors) which I wear both over soft headgear, and under helmets.  

The vehicle mounted MSA sets I've used were the "behind the neck" style, and IIRC, both companies sell "behind the neck" versions, but personally I prefer the over the head versions.  Once again - they're comfortable enough, though the MSAs pinch my head and begin giving me a headache after not too long...

Needless to say, wearing a headset under a helmet is not more comfortable than wearing the helmet without it... but then again, wearing a helmet is not really the most comfortable thing in world, either... you do what you need to.  

As far as I know, there's no way to mount a headset with ARC adapters to a TC2000-style "full" ACH/MICH as the ear "flaps" will get in the way - hence the popularity of "high cut"-style helmets.  If you have a TC2001 style helmet, of course, then mounting them on the ARC rails would probably be your best bet.    

I currently have an Ops Core Base Jump, and would love to pick up a ballistic one day in the future, and plan to mount up a set on the ARC rails.  

~Augee

I have a Yeasu ft-60 and I was looking to use a speaker mic like this one, with a 3.5mm patch cable to the ear protection.  

Link to speaker mic