The fs2000 has some great things going for it it actually has a 16.5" barrel I believe. It's also a gas piston weapon which makes it superior. You cannot change length on the weapon though. That is to say length of pull is not adjustable. This is important because it limits you to a weaver style stance when firing. That is un less you have very long arms. Also I hope that your right handed because despite the fact that the gun is forward ejecting its not very ambi friendly. The charging system is the same as the hk91 or mp5 and the bolt hold open operates the same as well. For a right hander this is a great gun. Despite the awkward feel the gun is actually designed to correct many problems with shooting positions and trigger pull technique. Hope this helps.
I have actually thought about the Tavor but I'm afraid the price will be more than I'm willing to pay. Also not sure how likely the Tavor is to come to our shores with the current political environment.
Then again, the ability to buy a Tavor is about the same as finding a FS2000 or even an AR at this point.
"For every problem there is always a solution that is simple, obvious, and wrong." - Mark Twain