Truthfully, I'm not sure I'm totally sold on the solar part. Since there have been some reported problems with the solar G's with some modules I'm not convinced that spending the extra for that feature is money well spent.
For example I have a 5600 and 6600 that have their original batteries from when I first purchased them well over 7-8 years ago. Batteries are proven technology, relatively inexpensive and easy enough to change that I think they are a good option. Now, I don't use the back light much or the alarms so maybe that's why mine have lasted so long.
Other than that, I think that G-Shocks are great watches and are about as durable as they come.
Mike