Just today I purchased my first (and only) 135L. I'd been putting it off until I learned more about the Rumored Siggy, but realized that I'll probably be able to sell my 135L for the Sigma if it's really so amazing. I'm sure I'll get back nearly the whole purchase price!
...not to mention that I'll have ten months using it! For what it's worth, the 135L is a stunner. I'm super excited.