Well, my ideal AR handguard looks like this:
1. Lets me place gear anywhere I want using existing mounts I already have.
2. Lightweight - lighter than standard handguards if possible
3. Smooth polymer everywhere I don't have gear
4. Helps handguard cool like a big aluminium heat sink
5. Free-floats the barrel
6. Has an uninterrupted monolithic top rail as solid as the upper receiver
Unfortunately, nobody makes that, so I make compromises instead
I think the VTAC handguard is probably the closest to my ideal right now; but I don't see enough of an advantage there that I am going to replace my old Daniel Defense 9.0 rail.
The big things I like about the DD 9.0 are:
1. Lightweight - the 7.0 with aluminium barrel nut is lighter than a set of M4 handguards installed.
2. I can put gear whereever I want (although in reality, there is really only about 2-3 places it ever ends up)
3. Better cooling
4. Free floats the barrel
5. Rigid enough to mount a T1 on and still have no zero issues out to 100yds.
Typically, it seems like many of the substitutes I see (Magpul MOE handguards, free-float tubes with adjustable rail sections) sacrifice some combination of 2-5.