I have been wearing this one since I got it. I was attracted to this model because I really want one of the high end "aviators" but dont want to pay that price tag. The GA-100 is priced reasonable and has a very interesting "cockpit" look.
I will start with my few "cons" and then conclude with the strengths.
I suppose one con is the watches greatest strength. Yes the watch is super, duper, high speed stealthy. And thats what draws a lot of us to this model. But those - display windows are about useless. Except in bright lights.... I have a VERY hard time reading them. Sexy, but not functional. I have am AWG-100 as well and there is a trick for reading screens with the LED powered G's. All you have to do is place your finger just over the screen, and the LED will light your finger enough to reflect light onto the display. But even that trick is hard with those - displays.
The small hand below the 12:00 position may bother some as well. This hand is used to with the tachy feature when using the chrono mode. The hand will never be centered. Because of this, some people may find the asymmetry a bit annoying. Particularly since the white hands really pop against the flat black watch. This doesnt bother me, but I did always wonder about it when looking at pics.
The GA-100 lacks a "button tone" or a beep when cycling through mode functions. I really wish they gave us a mute option instead. Because the screens are so hard to read, having that tone to help me know if Im at my home mode or not would be helpful.
I think the lay out of the screens in the time mode is a little odd. You do have two choices. You can display the DAY and time OR the day, date and seconds. I realize its a style call, but the layout is odd. The screen on the left at 7:00 displays the Month and Day OR the time. Well its really easy to confuse 12/31 with 12:31. Then the screen on the right at 4:00 always displays the day and seconds. I find myself searching for the seconds sometimes and having to "think" about the display a bit... when I can see it.
Well, just look at it! :) This is one cool looking G. Its a nice fusiuon between "Street cool" and "tacti-cool". Kind of like the watch a SEAL may wear out to dinner or a club LOL. Seriously though, its a great looking watch. The hour markers are really cool with a "3-D" effect. And the whole dial has depth and presence. There is also some really nice detail work on the dial.
For an analog G, another strength of this model is the legibility of those hands! They REALLY pop off the dial and that makes it one of the sharpest "at a glance" watches out there. I have no problem quickly rotating my wrist and determining the exact time. 11:11... now I have to search for those dim seconds LOL.
The buttons (while lacking the tones) are really easy to push and a fantstic size. Nicely textured and even use-able with thin to medium sized gloves.
The fit is PERFECT for me. I have a 6.75 inch wrist size. If you like the 7900, but wish it had a LITTLE lower profile, the GA-100 may be a good watch for you. As much as I LOVE tall watches, this one sits lower on the wrist thatn many G's and thats a good thing to me. It has a very sleek look and feel despite its size. Dont get me wrong, its beefy, but not obese.
Oh, one more for looks. Come on... black stealthy watch, popping white hands, and UBER cool orange LED. That light looks so neat its just AWESOME. And it really makes the white hands legible in darkness. (Just dont go looking for the seconds ).
The buckle on the GA-100 is double tang and has a nice wide buckle. Its got a very tough look and I really love the use of the double tangs.
From a techno-geek perspective. Although I never use it and really dont "get it" the tachy function on this watch is kind of new and "revoloutionary". They did a neat job of coming up with somethign unique for this model. I dont think I have ever seen a tachy function like this. Im more used to the one on the bezel of my G-1100B.
Over all, I think the Pros win the day. This watch is awesome.... as long as you know what you are getting into. Dont expect those displays to be as bright as they appear in many of the pictures. If you like BIG G's (that in this case wears reasonably) then the 100 may work for you.
And here are some shots of the other referenced G Shocks: