looks quite okay, but the mechanical look is a bit "crowded" for me

4XX can get
it is matte not glossy.

I don't have a GD-350, but I'll try to help

1) if by "shock absorbers" you mean then part that connected to the band that fills up the gap between the watch and your arm, then I'd say it's not much of hindrance. I have a G-7900KG-3 that have the same thing, and even after a whole day of putting it on I don't feel anything that can be classified as "uncomfortable"

2) I'm not sure, and I don't think so. as far as I know G-Shocks that have such function only comes in very few models, and the only one that came across my mind is the G-7800, which I happened to own one in the form of G-7800B-1

that maybe depends on how's your wrist size or how tight the straps are, but you'll get used to it..

as far as the appearance is concerned, the G-7800 can even change the placement of day & year aside from the usual day-month, display font size and even the display contrast. review here

the size is similar to the 5600 series. got mine for RM370 if I can recall correctly, from a shop in Sg. Wang. bought it in somewhere in Jan 2010 and that time it's already quite hard to find although it's a 2009 model, maybe coz it's not that popular

nowadays can hardly find a shop that have 7800 in their stock