Correct me if I'm wrong.. but for the Reavers, the Cluster Caltrops is d6 str 6 autohits on the flyby, and the Grav Talon is d3 str 4 autohits with potential for pinning on the flyby...
I understand that, should you pin something you will be very happy and do a little happy dance...
But Space Marines (and let's face it, most of the time we will be facing space marines) are typically very resilient against pinning, and your chances of getting it are very low.
It seems to me that for a few points more, I'd rather kill more with more hits at a higher strength and force a leadership test through dead models instead of trying to pin.
What do you guys think? Higher numbers of higher strength hits for more points, or a lower-cost upgrade for fewer attacks at lower strength with the chance to cause pinning?