I got a 2017 in August of last year for $10,200 OTD with the three extra years of extended warranty. The GT wasn't available around here at that time, but now they are listing for about $13,000. Add the extra warranty and taxes and other BS and I'd probably be lucky to get one OTD for $15,000.
I added a Corbin heated seat, Madstad windscreen, McCruise, Givi crash bars with highway pegs, Yamaha heated grips and rear rack, rubber topped foot pegs and different hand guards. I already had a top case. All of these additions came in at just under $2000. So for $12,200 the FJ has everything the GT has except for the extended swingarm, the TFT dash, quickshifter and hard bags.
Even if I had the GT I'd still want everything I added to the FJ except the cruise control which it already has. That would bring the cost of the GT up to about $16,300
So for $4000 less, or $3000 less if I got hard bags (which I don't want) I think I did well to go with the FJ-09.
Edit: I also added the quick shifter later, an easy install on the 2017.