I bought these because our guinea pigs like to chew on the bars, so we covered them with fleece. However, fleece-covering only made it difficult for them to see us and for us to see them. Their enclosure looks very snazzy with the new windows. They deeply enjoy it!
It provides good enrichment for them, as they can now easily see us moving throughout the room. It also has helped our more skittish guinea pig become less shy. It may sound strange, but my theory is that he was more skittish because he could not see us approach the cage. Now that he can see what and who it is that is approaching, he is much less prone to hiding.
Absolutely a good purchase if you have bar-chewers or want a classy enclosure. (It truly looks like a fancy cavy suite!)