Mick,
How reliable are the G1000 with dust, dirt, rough strips?
Seemingly not too bad, worked in a company that had 4 aircraft with the G1000 that operated in somewhat bush operations. The pilot pool, management and engineering leadership were completely indifferent to the issue of dust ingress so they got a fair exposure. I only did about ~200 hours with the G1000 over 4 years and found it easy enough to use and fairly basic.
They do have failures from time to time but as I said not too bad. Pretty modular design so the offending component can be removed and replaced.
My feeling is the test for reliability starts at year 5 as repeated heat cycles, vibration, moisture, dust etc. takes its toll.
Personally I still prefer analogue systems (although now fly the Primus Apex system) and even more so for day VFR ops. But analogue or G1000 would be a toss of the coin when emotion is removed.
Give some long time operators a call is the best bet.