Canon, my opinion below average cameras, but the best lenses.
Now Sony...
I forked out £180 for the standard Sony Alpha 75-300, so expect around that price.
It is however possible to pick up cheaper lenses, Minolta etc, i can't remember which one is for canon, and I believe they're around £100, but I assume the quality is worse.
So it's whether you want to risk spending £100 and being possibly disappointed or just go for the Canon one, which will, undoubtedly be high quality.
Some nice pics as well Mikey!