I quite like the FS2K
I have a few different bullpup platforms, and I like the FS2k. I would say it's not as robust as the Tavor, but it is more refined. I've had AR's since the good old days when 30 round mags were just that, and the 20" version was non-restricted. I've since abandoned my AR's in favour of bullpups. It was, for me, an easy transition to a type of design that I believe to be superior in both engineering and ergonomics to carbines I've used in the past. I'm physically not that large a person, and I therefore find it easier to shoulder and stay on target for protracted periods of time, a carbine with more weight at the rear, as opposed to being ahead of my dominant hand. The weight, balance, and compact size of the FS2K were quite handy to have on our last hunting trip (wild boar). At the end of the day, my gps indicated just under 20k of slugging and running, and my legs were tired, but I didn't feel it in my upper body...Here's a glamour shot...
The FS2K is a little thicker than the Tavor, but it isn't noticeable when using the gun. Pictures of the rifle don't do it any justice, you need it in your hands to see how small it is. Mine has been re-barreled to Non-Restricted length, and that is a huge bonus. I purchased my FS2K in the standard platform with the factory optical sight. Doing so allowed me to pay for the re-barrel, and defer the cost of installing a different optic.
Here's a picture of the gun with factory optic, and NR barrel...
And here's the new glass with the lowest mounts I could put on the rail hidden beneath the optic shroud.
If you want to re-barrel the gun, it's going to cost you an extra 600-800 scoots - add glass & mounts and the price is going to get up there... but for me it was worth the expense.
Good luck with your search
Cheers,
M