If you are liking the 2014 models go for it! They are a great vintage of FJR. Better cruise control limit of 100 mph and that hot Lipstick Red paint!
I have over 440k miles on Gen I FJRs, 160k miles on Gen II, 80k miles on Gen 3, and 57k miles on Gen 4 so I like to think I am a lot smarter than I actually am. They are all good. But I will concede that I think the sweet spot is Gen 3, 2013-2014.
2013 has the lame cruise control limit of 82 mph indicated, 80 mph actual. This can be addressed by replacing the ECU with the '14 or '15 version, or getting the ECU flashed by Ivan. 2013 and the start of Gen 3 also introduced all the other goodies like heated grips, ride modes (not a big deal to me), and traction control. Also, stock suspension was a very notable upgrade from Gen 2 to Gen 3.
2014 increased cruise control limit to a more useful 102 mph indicated, or about 100 mph actual. In 2014 the Electronic Suspension model was introduced. ES suspension is a love/hate thing with some folks hating on it. I think it is an excellent compromise for the vast majority of FJR owners. But a compromise it is. If you want truly high performance suspension ready to rail in corners and on the track, or if you are a portly kind of guy, get the A model which has decent suspension, but spend the big $$$ for custom shock and fork springs and valving.
Gen 4 with the start of the 2016 models brought the 6-spd transmission. My slight preference is the 5-spd. While I like the slightly reduced rpm of the 6-spd at high speed cruising, the shift quality is not as good as the 5-spd and frankly, it's just another gear to shift. The 5-spd gearing is really the sweet spot for the FJR as far as I am concerned
Gen 4 also brought the slipper clutch which is nice for the reduced clutch effort. (It can be retrofitted to older FJRs) Also the LED headlights which I think are a HUGE improvement over previous halogen. As far as I am concerned, the cornering lights are just about useless. Only slightly helpful at parking lot speeds.
The other negative is all 2016-2020 FJRs had to have the engine torn apart for the 2nd gear recall. Not a lot of problems associated with that, but ideally I don't want my FJR's engine torn apart and put back together.
To me the biggest flaw of Gen 3+ FJRs is the weak cast aluminum front subframe that can break at the mirror mounts simply from an FJR drop. PITA to replace. A bit easier to repair, though still a PITA. Get some type of crash bars to lessen the likelihood of that problem in a tip over.
This summer I spent 8k miles on one of myGen II 2009 FJRs riding all across Europe and loved it! A great FJR. Even with just a simple throttle lock. It has custom suspension and handles awesome!