Looking at getting one for rugged use.  Not climbing Mount K rugged, more hunting, kayaking, camping, and nice sporty-wear use.

Thoughts on it or equivalents?  https://www.gshock.com/watches/master-of-g/gwg1000-1a1

Would be better if it had solar

FPNI

I wouldn't be interested at the price it goes for. I'd scoop up a Casio 5600, 6900, or 2100 before spending that much for a Mudmaster.

Interesting features and comments from an antidotal perspective:
  Atomic clock - It's a quartz. Set it and forget it. I don't value an atomic wrist watch as much as I value an atomic deck clock that I use to set my watches.
  Altimeter - Cool feature that I likely wouldn't use often. I like to track it when hiking or mountain biking, but I'd rather track it with a legitimate GPS.
  Barometer - I don't value this information hardly at all. Even shooting long range, barometric pressure has very little to do with my life.
  Thermometer - Another interesting feature, most of the time I actually need a thermometer is when I'm measuring hot water or food. I'm not going to stick my wristwatch in it. Atmospheric temp is handy shooting long range, but I'd rather rely on my Kestrel or IR gun.
  Digital Compass - Cool feature. Could be handy at times. I like the idea of having an extra one with you on your wrist. Could be handy hiking and mountain biking.

I typically prefer to have a specific tool for a specific job. I want my watch to tell the time, and my thermometer to tell the temperature. The features are cool if you plan to use them.

For a super tough quartz watch without those specific features in that price range, I'd look at a Sangin Professional, CWC Quartz Diver, or Resco Manus. For a cheaper option, consider a Citizen Eco-Drive Promaster Diver.

Stay away from Luminox as a whole. The one I have will be the last one I ever own.

At the end of the day, if you like the watch, buy it. There won't likely be a 'real substitute'. However, if you're just considering if it's a good watch for the money, I'd say you can certainly do better unless you want the specific features it offers.

I had the tan one, but honestly it was fucking huge and I didn't use a fraction of the functions. I sold it for close to what I paid for it and picked up a GW9400-3 "Rangeman" for a fraction of the price ($250). I still don't use all the functions but it's very accurate and tough as hell plus it's solar powered which is nice (still fucking huge though). I use the Rangeman on duty and while working on my farm or cars. I have other automatic watches but having the G-Shock is the worlds best beater, and they certainly have their place.

They are great watches but too chunky for my liking.  I went with a G-Shock square (digital).  I like the smaller size and throwback looks.

I agree, Rangeman gives you the same tactical look (but digital) plus solar for a fraction of the price

How does one even begin to shop for a g shock?   What are the core models or vintage ones with .mil heritage?

IMO, it needs to say atomic and solar.  I'll never use a watch altimeter, but it is nice to have a watch that sets itself, and I don't have to worry about changing batteries.  

It depends on your needs and budget.

Imo, the 7900 series are your basic, daily wear, beater watches. Sturdy enough to survive moderate abuse, decent options, and reasonably priced.

The 9400 Rangeman is the next step up. Chunkier, and arguably sturdier...but almost 3x the price of a typical 7900.

If your pockets are a bit deeper or you want/need something bombproof, look into the Master of G line.

The rest of their primary lineup (6900, 5600, etc) is really more fashion oriented than performance. The 5610, for example, is an awesome daily wear watch...but it's not the one I'd reach for if I was going on an expedition, mountain climbing, or jumping out of planes.

I have a 6900, two 7900's, a Rangeman, and a Gulfmaster (the old model, not the new cheap one), and the first three rarely get worn.

You are seeking the GW-5000-1jf

I was told this and finally snagged one.

Best G made. Screwdown steel case.

Very nice and appealing