A reason not to buy a Sony product, is absolutely the Memory Stick. In our homes, there is certainly an SD card floating around, from cellphone, digital camera, even the Wii. Instead, the memory sticks are expensive and nothing except Sony products can use them.
A Memory Stick is ABSOLUTELY more expensive. Here is a comparison on a 16 GB card, from the same manufacturer (Sandisk):
Paying 24 euro more for essentially the same product! Who will pay a "36% Sony tax"??
So, the great idea to lock Sony users with the Memory Sticks, has proven to be not so good: it renders the product less appealing!
Recently, on new cellphones, and on expensive cameras, Sony chose to use "standard" formats. (microSD for mobiles, compact flash for D-SLRs). Now they confirmed it!
The next step? As Engadget says, they could kill the UMD. Oops, they already did it 