I have metal buckles on my early version sentinel but noticed they went to plastic recently. The only thing I don't like about the sentinel is the stitched seam on the waiste strap will ocassionally get caught in the buckle and is a real PITA to pull out when tightening.
I've dropped many devices or pieces of a device redirecting, moving TIP, trying to clean sap off a hitch cord or in the device - HH, RR, etc. Knowing a closed old-school MRS has come in handy a handful of times.
But, I'm not going to hammer the OP. I remember the first time I used a foot...