They are an excellent source and I recommend them highly. They are Mac specialists and their stuff is guaranteed for life.
BTW, I just got a check for $310. from the Attorney General of the state of Arizona because of the alleged price fixing by DRAM Manufacturer's between 1998 and 2002
Used RAM on ebay. Verify with an overnight run of memtest and it's all good. If memory is adequately cooled and handled properly then failure rate is vanishingly small.
I do stick to quality RAM, and for Mac Pros always get DIMMs with heat spreaders.
I won't buy this one, the "Detailed Description" is totally mismatch with the title.
The title is "Pacific Sun Memory DDR3 16GB PC3-10600 ECC Registered Dual DIMM Memory"
But the details actually points to "2x8G DDR3 PC3L-10600 Non-ECC Unregistered...."
Also, it's better to buy 2Rx4 memory. Some RAM are 4Rx4, which may run at lower speed in the cMP (e.g. only able to run at 1066MHz even though the spec is 1333MHz if you fill all the slots).