Is there any reason to buy the 2x4 kit as it seems to be more expensive for some reason.
Kits in general are marketed as tested working together at factory, but I have not heard or read anyone having issues with these single-sticks.
Newegg reviews for the single-stick 4GB is rated at 5-star at 92%, and I see lot of reviews with positive results with or without overclocking.
Buy these from a vendor with good customer service and if they don't work well just return or exchange it.
Like the OP says these are indeed magical RAMs. It's difficult to comprehend the fact that it is so small yet so powerful and operates at a very cool voltage. This ram is like Moses, but instead parting the red sea it parted all the grossly out-of-control heatsink rams in the market.