I switched from a launch 360 to an elite and to me, there is a difference using HDMI. Not a big one, but some. The colors were more vibrant and the sharpness was better. If your Sony receiver is only component in and HDMI out, then forgetaboutit, not worth it. If you have HDMI in and have the extra cash, might be worth it.
Also, your TV size matters. If your using a 32" HDTV, don't do it. I'm running a 120" HP screen and right off the bat I noticed the difference. If you have a friend with an HDMI out 360, ask if you can try it on your system.