I am having the same issues. I have tried it on three different mac's, all versions are doing the same thing. So your not alone. I just stopped by the forums to see if anyone has reported it already.
For me, I am running the following spec machines. All have java 1.6.x
MacPro, 8 core, 32GB RAM, 10.8 (Mountain Lion)
MacbookPro, i5, 16GB RAM, 10.9 (Mavericks)
iMac, i5, 16GB RAM, 10.8 (Mountain Lion)
For what it's worth, I have tried to reinstall the client and the end result was the same. Oddly enough, there is absolutely no error logged to the console. The last line in my log file is : [INFO] MCLauncher.launchMinecraft:103: Defaulting PermSize to 256m. I even tried the new .app launcher but it keeps giving a popup alert style error that only says "JRELoad Error "
Anyway, i'm not asking for support, just saying I have the same error too across several machines so it's not an isolated issue and your not alone. Hopefully someone has already logged an official bug report.