I had decided to buy a Pro Set Elite 6 headset from Universal Radio while I was in Columbus this week.
When I called they were out of stock!

My options would be either a Pro Set 6 or a Pro 7.
If you have used them is the Pro 7 $100 better than either of the others?

My primary usage will be on my K2 learning to operate CW.  So that I don't annoy everyone else in the house.
Secondary usage will be SSB on my ft-747 & the K2.

I know that I have many other mail order options.  
Universal Radio is just my primary option for a walk in amateur radio vendor and I'm nearby about once a month.

No way is it even a dollar better.

The only difference between the two of them is the greater external sound isolation of the larger, heavier earcups and tighter headband. I would argue that is a huge downside unless you are playing radio in a high ambient noise environment. They will wear on you and give you a headache.

Don't buy into any of the Heil marketing hype. If you are handy at understanding the pinouts on your connectors and don't mind doing a little connector soldering, any moderate quality PC type headset will sound as good as a Heil headset.

aa777888-2 knows what he is talking about.  Many cheaper alternatives that are just as good.

Also not a heil fan.

I am a radiosport fan though if you want to spend that kind of money.

Otherwise find a nice normal pair of headphones with a boom mic for much less and rock on.

I have a set of the Heil pro 7 for icom and they work well, but I still use my sony headphones from bestbuy 98% of the time.  Cant tell a difference in sound and i dont use the mic on the heil..  I have a icom sm-8 desk mic that works so well I dont use the mic attached to the heil.  Just dont feel comfortable with the heil weight and how it feels.  Kind of like wearing a helmet..    If you are in a noisy environment the heil will shine as they are extremely well at muffling background noise...    

Good Luck

Prosise

I have a set of PSE6 and they are nice.  Probably a bit of overkill but I wanted something that I wouldn't say 6 months down the road, I should have done this or that.

https://www.amazon.com/Technica-ATH-COM2-dynamic-Combination-Headset/dp/B0002X600O/?tag=vglnk-c102-20?tag=vglnk-c102-20
I've used the Audio Technica ATH-COM2 for a long time with good results. Unlike computer headsets they have a dynamic microphone element.

I forgot to mention that my primary and secondary usage are both Icom units and there's an extra cap or diode that they needed for the mic.    
With the Heil it was, plug and I can play.

A few months ago I was musing about adapting an aviation headset to amateur radio use. 

I think BigDaddy did that.

Yes, I've had these David Clark H10-36's adapted for my IC-7200 for a long while.  Like aa777888-2 mentioned above, they will mash your head after a while and give you a headache.  But, if you're in a high-noise environment, they work great.  I got them mostly as a novelty because I've used them as an A&P mechanic for a long time.

I'm married so I am in a persistent high noise environment.

This is a little bit of thread drift, however, in the spirit of general headset interest: I fly helicopters with the doors off, and it doesn't get much noisier than that. I have, just like pretty much any other pilot out there, the usual bread and butter, meat and potatoes, David Clark headset. They are rugged, reliable, and reasonably quiet. At the same time, they are like wearing friggin' Vice Grips on your head.

I thought about blowing big bucks on the usual lightweight solution, which would be a set of Bose or Lightspeed active noise reduction headsets. But they can still be quite sweaty in the summer, and if the batteries STB then you have no noise protection at all. So instead I decided to go the "communications ear plug" route (or "CEP"--that's what it's called in the pilot world). Pictured below is my Clarity Aloft headset. It normally uses a set of Comply foam eartips. The Comply eartips are a million times better than the regular foamy ones, but they are still a pain to put in, and impossible to use in the winter when they are frozen solid. So I had a local hearing aid place make me a set of custom Starkey earmolds. I had to send the entire headset in so that they could mold the backside as well. Now the headset is arguably quieter than a Bose, uses no batteries, is a dream to wear, and I can put them on and take them off much more easily and in any weather or temperature.

I did not like the Elite version. They were too bulky and less comfortable than the regular pro-set. I bought mine with a HM-4 micropnone element because I use the headset mostly for contesting.
The pro-set headphones sound great and I can wear them all day long without fatigue.
Beware that you need a DC blocking capacitor if you use a Heil dynamic microphone with an ICOM rig. Heil Icom adapters already have one.

I have a similar David Clark headset (H20-10 model) back from my flying days. They have a gel filled muffs that makes them very comfortable and blocks noise very well. The only complaint is that it makes my ears sweat a lot in warm weather. It was not a bit issue when I was flying because air is always colder at flying altitude. It can be in a shack though. I may try building an adapter for them to fit my HF rig.

I have always hated the earbud headphones.  I never felt like the DC or other headsets felt like a Vice Grips.   I guess that is why they make different headsets.  Earbuds drive me nuts.

I have the Heil PSE6.   It takes a bit  of fiddling to get them comfortable, but the head band is meant to be bent back some to get them to a comfortable setting so they don't squeeze your head.  After a while the ears do get warm in them, however, when operating in a warmer environment.