They are not in the same class.
Both are hard disc drive based - right off the bat, they would fall off my list just for that... but here goes.
Both have a built-in infrared emitter for zero light video capture ("NightShot"). Video will be poor and in black and white. I HOPE the XR500 would be better in the dark, but combining AVCHD compression + small lens + small imaging chip, the low light behavior is similar.
The ENTRY level SR65 has no mic jack. It records only to a very highly compressed MPEG2 standard definition video format. This typically requires conversion to a more useful format before editing. The only audio control the SR65 has is in the menu - "Normal" or "Low" gain (for loud audio environments). It retails for about $500 if you can find it. Sony discontinued the product,
The XR500 is an expensive consumer camcorder with a mic jack and manual audio control. It saves to a very highly compressed high definition format called AVCHD. The MTS files can be a bear to work with.
For editing, your computer needs to be fairly new (and really fast), have LOTS of RAM and a hard drive that is NOT the startup drive so you have a place to store the video project files. Older versions of video editors cannot deal with AVCHD video. MovieMaker can't deal with AVCHD video at all. The current versions of Sony Vegas and Adobe Premiere float to the top. Or, in the Mac environment, iMovie '08 or newer or the current versions of Final Cut (Express or Pro).