You'll find that most people here will probably recommend the Sony's over the Canon (myself included).
have the trv33 for £495, so this is well within your budget - there'll be money left over for tapes / spare battery / case.
When I was looking to buy (I ended up with the trv33), is was also considering the Canon, but was put off by reports that the tape mechanism is noisy and is picked up by the on-board mic.
The Sony's are easy to use. Some people complain about the zoom lever being too sensitive, but once you get used to it, it's not an issue.
As far as night/low light use is concerned, most mini dv camcorders fair badly unless you're prepared to spend thousands. I've taken footage indoors with just the room lights on and the results are not brilliant, but they are acceptable. You can always purchase a light to fit on the hot shoe of the camcorder if you want better results.
The Sony's night shot mode is actually quite good in that it uses an infrared light source, so the footage comes out black and white with a green tinge.
Finally, the sound on the Sony is excellent (in my opinion). Again, if you want better, you can always attach an external mic.
If you do buy the Sony, I'm sure you won't be disappointed.