I recently purchased a Giant OCR-C3 with 10 speed 105 group. I've since put around 500 miles on the bike, maybe a little more. Real happy with the bike.
I did my quarterly check of my bikes which includes checking chain wear using a Park CC-2 Chain Checker and found the 10 speed chain shows significant wear with a reading of 0.75 (.25-.5= new chain, recommended replacement at 1.0). I usually replace at .75 wear mark. That means I only got 500-600 miles from this chain! This is a real expensive PITA if I have to change chains every 500-1000 miles. I'm very easy on chains. As an example, my old Cannondale, with 105, 9 speed has about 1000 miles on the chain and is still reads below 0.5 = new chain specification.
So what's with the 10 speed? Any thoughts? Oh, I use chain lube every two to three rides.