you will find your books listed together. The vertical list (not the horizontal one) will show ratings and review counts. If you keep track of your review counts, you can see at a glance there, if anything has changed.
On Author Central (authorcentral dot amazon dot com) one of the tabs gives you reviews in reverse chronological order--newest first. It says New next to ones that are new since the last time you visited the page. This only works however for US reviews.
There are several web tools you can use to get sent change alerts to pages. I use them for other purposes but you could use them for amazon page change alerts most likely. Here's 5 you could try. I use change-alert