I aways use the clutch. Not that big of a deal to me. But I'm curious. For those of you who don't use the clutch (much), do you notice a lot of metal particles in the oil? I would imagine that would have to wear on the gears a bit more.
When properly executed, the "clutchless" shift, or speed shift as it's sometimes called, can actually be easier on the transmission parts. It takes a lot of practice and much familiarity with the bike, its various power curves at varying speeds etc., to speed shift smoothly all the time.
I purposely inspect some my oil changes for metal particles using a coffee filter and a magnet, to see if anything is showing up. The only time I find noticeable particles is whenever I have been over using the clutch, not when I've been "underusing" the clutch.
I use the clutch for N-1-2, almost always speed-shift 2-3-4-5, and rarely attempt downshifts without the clutch. If I want to make a super smooth shift without the need to "blip" the throttle, I will pull a slight pressure on the clutch without fully releasing it just before the speed-shift.
Dirt racers habitually speed shift. The comination of the dirt surface and the chain drive provides more than enough slap/slack to allow a smooth mesh transfer. It shaves milliseconds off the lap times with each shift. Milliseconds eventually add up when you are shifting constantly. The habit/practice has never been an issue for me on street bikes since the late 70s models.
The FJR with its shaft drive, does not have the luxury of "chain slap" for shifting tolerance. IMO, the FJR requires a more precise throttle blip than chain bikes. Another common side effect of speed shifting is rear tire wear. Every rapid shift scrubs a bit of rubber unless you manage to hit it 100% accurately. Only the AE computer is capable of repeatedly shifting that way.
To me, the worst thing about speed-shifting, is the embarrassment when you miss a shift and have to back off, clutch and try again. It's like pulling out reading glasses in a topless bar.