I recently purchased the GW2310 and would like to share some thoughts about this jem of a G-Shock:
(1) World Time: First of all, it does show home-time and world-time together. In home-time, push the top right button, and the world-time comes up above the home-time. Now this is a great feature, which gives you the best of both worlds. A quick push of a button in home time mode will swap the month-date for world time. Or, if you are traveling and don't want to reset the home-time to the new location, just go to world-time and there you have the time, month, and date all there, just as if you were still in home-time mode. I don't know of any other G-Shocks that show the month and date in the world-time mode.
(2) Stop Watch: I have read complaints that the current time isn't displayed in the stop watch and timer modes, like some other G-Shock models. I think a simple explanation for this is because, in stop watch mode, the most important thing for the watch to be doing is acting like a great stop watch, which will keep giving you 1/100ths of a second lapsed, even after the first hour has past. As a highly accurate stopwatch, the ability to measure 100ths of a second as long as the stop watch is running is more important than simultaneously showing the current time.
(3) Timer: Similarly, in terms of the functionality of a countdown timer, it is more important to see the set countdown time and the minutes remaining, to make a quick calculation of how many minutes have past, than to show the current time. Like the world-time and the stopwatch mode, the countdown timer is keeping its mind on the job at hand - being the most informative countdown timer it can be.
(4) Alarm: Again, the alarm is telling you what you want to know. Generally, I want to know what time it is now, while I set the alarm for later. For example, "Okay, it's 12:30am now, and I want to get up at 6:30am ..."
(5) Auto sleep: It goes into sleep mode after sitting still for an hour - great power saving feature.
The watch's two biggest drawbacks - and they are significant ones, are the alarm volume and the band. For a tough looking watch boasting 5 alarms and a countdown timer, I would have expected the alarm volume to be a lot louder than the demure little squeak that it is. Also, the band is a lot stiffer than my other G-Shocks.
As for the alarm, I can only comfort myself with the knowledge that most of the other G-Shocks suffer from the same problem. The DW-6500E is a little better, and the W-71 is much much louder, but the trade off of features is too much for me. Besides, after a few weeks I'm getting used to the alarm, and I'm starting to notice it more, even with some background noise.
And as for the strap, I'm getting used to that too after a few weeks. Although, just as a stereo is only as good as its speakers, a watch is only as good as its band. So, I bought some adapters and a maratac 24mm 2 ring zulu. Looking forward to them arriving in the mail soon. (Unfortunately, the 2300 specific adapters in black are not so easy to find. Tiktox and some other retailers have the adapters in a silver/grey color, but not a black that matches the watch case. I think these black adapters went out of production with the G2300)
All the best.