I don't feel particularly strongly either way.  I just went with my experience from the .NET world, which basically says that you shouldn't have more than 2 uppercase letters in a row.

For example:
 - `System.IO` = "good"
 - `System.Web.HTTP` = "bad" (should be `System.Web.Http`)

It's relatively unimportant but lots of uppercase letters can definitely make longer names or multiple consecutive acronyms very confusing, e.g. `XMLHttpRequest` could've been even uglier as `XMLHTTPRequest`... though, by the standards I've mentioned, it would've been `XmlHttpRequest` instead (which I admit I find easier to read, personally).