Gear Combo Guru
Join Date: May 2007
Bikes: Spec' Tarmac (road), Ridley Fenix (commuter & fast tourer), Salsa Mamasita (MTB), CoMo Speedster (tandem), Surly Big Dummy (cargo), Airnimal (folder)
We're also using a mix of A520 and A600 pedals on our road bikes and tandem. We've had many pairs of A520s on many bikes, and have recommended them to many friends, and I've never seen a pair with a problem.
The A600s are about 30 grams lighter (about 100 grams lighter than your A530s), but as mentioned above the anodized surface does start to scratch/wear off with use, but that doesn't make them look too bad unless you're looking closely.
The body of one of our A600s did start to come loose during a tour last summer, a problem that I've never had with a A520. It still functioned fine, and loosely tightening it by hand a few times kept it going fine for a few hundred kms until I figured out how to solve the problem permanently, and they've never given any other trouble since. Therefore, if the price difference between the two is not too large then I would go for the A600s.
As well as weight, another drawback of your current A530 pedals is cornering clearance - that platform does stick out a bit too much for my liking.