which is better? avatar avenue or OP's site.
Judging the two at their current states, OP's site has the features that are still under development over at AvatarAvenue (such as resizing avatars and adding borders/effects to images).
On the other hand, there are NO bandwidth caps over at AvatarAvenue, and you have the option of using a random.jpg rotator or a random.gif rotator (as far as I know, OP's site is only "random.jpg", and on AA, you can name your random file whatever you want - like mine is "PGG.gif"). Another cool feature of AA.com is that you can track who's viewing your avatar and see how many hits it's getting. So, you can see the IP address of whomever is viewing your pics and where they are viewing it (whether it be on this board, JPM, or where ever).
So right now, in my HONEST opinion, both are about equal. Hallospacegurl's rotation is on Avatar Avenue as well, and there's not much of a difference between her rotation and say, Feel_My_Mind's rotation. The only reason I'd probably say go with AA is because it is already open to the general public, meaning that you get instant access to the features in place. OP's site is currently by request, so you may have to wait a bit so he can fill your request and add you.
I recommend though doing what HSG is doing - use both.

So if something ever happens to AvatarAvenue, you can always switch to OP's service.