A Google Webmaster Help thread has complaints from some webmasters on how Google's Cache view doesn't render all web pages as they are seen in a typical browser.
Let me show you an example, if you view the cache of this site in Google, you will see it doesn't necessarily rendered it too accurately. Here is a picture:
I personally never even thought of this as an issue, I just took it for what it was. But some would like their sites to appear as they do in a browser, in the Google Cache.
Now that Google has built a browser, Chrome, I can't see it being that incredibly difficult to make the cache rendering a bit better.
JohnMu of Google replied to the thread, saying he will pass the suggestion along. He said:
I'll pass your worries and examples on to the team, thanks for posting.
That said, I don't think it will always be possible to get this right for all pages and browsers, there are just too many combinations that make it non-trivial to get right in all situations. We'll see what we can do :)
Forum discussion at Google Webmaster Help.