I have both watches and in my own personal opinion the Mudman is the better choice of the two. The 2300 is to small and just does not feel like a true G-Shock; I prefer big watches so the 2300 I have I don't wear it that often. Besides the Mudman has a compass and a thermometer which will come in handy; functions which I have NEVER seen offered in the 2300 family of watches. I think the only reason I keep the 2300 is because it is the watch which saw me through two tours of duty in Iraq so in my mind it has earn its place in my collection. However, I don't wear it that often.
I have a G2110-1 which was the battery powered non-solar version of the 2300. And the 2300 family of watches were the solar powered, but it is basically the same watch.
Stick with the G-9300 you will like more I think. You know they offer it in navy blue with a negative display now.
Well hope this helps you make a decision. But remember at the end it is you who must wear the watch.
Here is an old picture of my battery powered non-solar G-2110-1.
Sincerely,
BB72.