When I saw that there was a Boonton 72BD 3-1/2 digit capacitance meter going for $100 on eBay, I couldn't resist. It's the tarted-up version of the analogue 72A that I have on my bench (and for which I paid $230, still a good deal).
It arrived today, and it's in perfect shape--if you zero it, the display sits there showing 0.000 pF all afternoon. It measured a bunch of 2% polystyrene caps to within 2%, from 100 pF to 1500 pF, and did a good job on other caps down to 1.0 pF (which are the smallest I have with leads). If you wave your hand nearby, you can make the display move by femtofarads very easily. It's almost good enough for a capacitive gauge.
I have a couple of projects for which I care about tens of femtofarads, so this addition to the arsenal is very timely indeed.
Awesome.
Cheers
Phil Hobbs