Pricey, but it works!

I purchased the 4GB Memory Stick Pro-HG Duo as added memory for my Sony PCM-D50 Digital Recorder.

Though I am not a big fan of proprietary memory (SD cards are a better value), Sony makes a fine product, and I am glad I bought the 4 GB memory stick. The HG is fast, and I ended up needing the extra memory while recording concerts in Europe.

If you shoot RAW buy this

I need to shoot bursts of RAW on a Sony DSLR-A700 for dance photography. The A700 has both an MS and a CF slot. The MS HG Duo seems to handle a stream of 18MB RAW files being written much better than the Sandisk Extreme III CF card. Maybe because the HG Duo and the camera were designed to work together from the outset. If you own one of the newer Sony DSLRs with an MS slot, this is THE memory to buy. BTW: The A700 is wonderful for dance photography where flash is banned and the light is abysmal and changing rapidly. Paired with a 70-200 Sigma f2.8 at 3200 ASA, it can track and take beautiful low-noise photos.

Not worth it if you own a PSP

I own a PSP, and use it to transfer music and videos from my PC to the PSP memory stick. I used to use a 1GB stick, wanted to upgrade to 4GB, read that the HG was sooooo much faster at writing and transfer speed. It's not. I transfered a 175 MB video using PSP media manager to both my 4 GB and my 1GB, to test how long it would take for each stick to do it. Both finished at exactly the same amount of time: 12 minutes. No improvement in transfer speed. I'm not happy with this product at all. If you're going to spend this kind of money for a stick for your PSP, you're better off investing in a 8GB stick. Or just shell out the $60 for a regular 4GB stick. Don't be a sucker. And whatever else you do, DON'T buy a stick off e-bay for $30, those are counterfeits!!! Then you're an even bigger sucker.