I too use the Avermedia box. This Elegato thing is new to me, but looks sweet. Can do HDMI, is PC compatible (I think), and has simpler wiring than the AVermedia box.
No problem hwang. If you're looking for fancier, an Elegato HDMI USB capture thinggie runs about $160. I use an Avermedia HD Game Capture device myself. That runs about $150, but you also need to supply a HDD for that one since it's basically a standalone DVR that doens't need a PC to operate.
The PS3 itself offers a decent video editor. Between that and exporting vids from your replay menu to the XMB, it wouldn't cost you any additional money hwang.