Sounds like something more localized. I've been getting WMT with no problem all along. We'll see if there are any other reports.
I just checked Twitter and I did find a few scattered mentions of some trouble - especially this report [twitter.com] that is close to what you are seeing: "Google webmaster tools is on a recursive loop..hm.."
The webpage at [google.com...] has resulted in too many redirects. Clearing your cookies for this site or allowing third-party cookies may fix the problem. If not, it is possibly a server configuration issue and not a problem with your computer
A small subset of users are seeing a "too many redirects" error when attempting to access Google Webmaster Tools. We are aware of this issue and are looking into it. In the meantime, you can access Webmaster Tools directly though the URL https://www.google.com/webmasters/tools . Thank you for your patience.