The military aviation museum in Soesterberg, the Netherlands has a full scale replica. Beautiful bird.
The G1 was quite advanced for it's day, bit it still used Fokker's tried and tested mixed construction (wooden wings with metal fuselage, but exact details elude me). I have an obscure booklet form the early eighties at home with lots of info, I'll dig it out tonight. This is what I remember:
Dutch pilots liked the D-21 more, it was easier to scramble and less complex. The G-1 was also only slightly (20mph) faster. The heavy aramament of the G1 (8 .0303 brownings) also made it nose heavy. Landings on soft fields frequently ended up with a G1 on it's nose.
Speed was decidely inferior to the 110 and 109 of 1940, but the G1 had to make do with Bristol Mercuries, The Netherlands did not produce high performance aircraft engines themselves. It's interesting to know that on the plans for the G-2 (planned successor to the G-1, never built due to the German invasion) DB 601's or RR Merlins were specified...
There is only anecdotal evidence on the G1's performance and flying characteristics but it seemed to have had a very high diving speed (dive brakes were installed on some aircraft) and that it was maneuverable.
The Dutch pressed some G1's into service with P&W Wasp engines, originally meant for export. They were slightly different to the Mercury engined ones and performance was slightly inferior. It seems that none of these saw combat, save for one or two reconaissance flights.
Most G1's were destroyed on the ground when the Germans attacked in the morning on the 10th of May. But even so, we only had a handful of them.
It remains the most advanced fighter of pure Dutch design and manufacture. Light bomber variants and reconaissance versions were planned and Fokker was hoping for export succes. This never materialized although some countries showed interest.
G1's that survived the German invasion or were still under construction at that time went to the Luftwaffe as destroyer trainers. Some photographs have surfaced, showing G1's in German markings as late as 1944.
One G1 even made it to Britain when a G1 destined for Germany was secretly filled with more fuel than specified by the Germans. The Dutch pilots who test flew this plane flew into a cloud and ended up in Britain. This plane survived well into the fifties and was used for (static?) experiments with radar. It was scrapped in 1954 or so. No original G-1 is known to survive.