I recently installed your plugin on a site I'm developing for a publisher:
On their product page:
http://www.halffullpublishing.com/products/gents-with-no-cents/ (click the tab for 'amazon reviews').
I've noticed this before, but the last couple of days it seems to be getting a little worse - namely it will stop pulling in content. This will last for a few minutes to what might be a couple of hours, then it will re-appear again. I do all the usual things, check the configuration, try different browsers, clear the cache etc. None of these make it re-appear until I check in some time later. Sometime updating the page seems to make a difference - but since this is for a client, I need to be as steady as possible.
Any idea what's going on? Is it the server, or perhaps something to do with Amazon?
Otherwise, plugin works great. The client's complaining so I have to check in on it.