What is the scoop on these rails?

Just my opinion after reading your Predator rail thread...

I was terrified of removing my barrel to install a FFT with rails.  I just knew I'd screw something up.  But I wanted to learn, so I bought the action block, the wrench, and a set of punches....

3 barrel swaps later, and it's one of the EASIEST do-it-yourself jobs I've ever done on a firearm!

I say, don't limit yourself by ruling out removing the barrel.  It is NOT hard, there's NO magic formula or secret dance...  

If you still don't want to "DIY", but you don't want to spend $300+ on the rail system, then Yankee Hill machine offers FREE installation of their tubes if you purchase from them, and don't have a permanently attached muzzle device.

Otherwise, if price isn't an object, the Troy Industry or SIR system are still better options.  After all, they still free float the barrel.

The ALOSTYR are very well made.  I have the rifle length and they are solid enough to mount my Aimpoint on them.  They go on just like a standard set of A2 handguards.  Until they happen to loosen up my AImpoint will stay put.

If you're not going to be mounting optics on the rail forend, what kind of advantage will a free float setup offer to a carbine?  
Any measurable decrease in group size with 5.56, 7.62 or .50 Beowulf out to 200 yards?

 Thanks,
  Dan

Yes, you'll find smaller and more consistant groups when using a FF tube on those calibers at that range.  How much smaller and how much more consistant depends on the individual rifle and the shooter's skill.

Quoted: The ALOSTYR are very well made.  I have the rifle length and they are solid enough to mount my Aimpoint on them.  They go on just like a standard set of A2 handguards.  Until they happen to loosen up my AImpoint will stay put.

Any chance of getting pics?  I'll host them for ya.