Nah, nothing like the old time-out issues. It shows the green box saying it was sent like it normally does and when I check my sent folder, I can see my copy of the PM chilling there. That said, there have been a few times where my message didn't go through and I didn't get a copy in my sent box, but that is rarer than the former and usually only happens if I leave the PM open for too long (an hour +, generally).
Running the latest version of Google Chrome, only using Adblock, Google Dictionary, Hoverzoom and Streamus extensions, if it helps.