UPDATE: June 2014. Still broken; crashes on quit. I can see almost no improvement in the last year for anybody but architects; for machine drafting, forget it. Does export to ACad formats now without crashing, which is good because I'm dumping it.
June 2014; for a year now I get the beach ball on exit.
It's broken by bad licensing methods. Help and support you pay for (listed for $95 in my invoice) are a joke. The main site now has a "licensing troubleshooter," that wastes a half hour of your time -- and no connections to real people or solutions.
Because there aren't any; Trimble has broken this formally great software and is now selling it to gullible people like me.
Sketchup Pro 2013 is NOT backwards compatible with Sketchup 8. That's what evil companies do. So I can't even go back to the old software, the stuff that worked.
I support nine good jobs, with a deadline two days away, with pencil and paper now.
Trimble, shame on you, fix this.
UPDATE! Got a great email from Tommy, asking me to check OS X disk permissions. Done this a dozen times. Same behavior on Windows 7. This "help" has been going on for a week.
UPDATE: After blog post I got a special call at work; generally respectful, but with a slight sneer I'm told that SU PRO 2013 is much more stable than the previous versions and beta testing proves that, so it must be something odd about my iMac (or me). [All the previous versions functioned flawlessly for me on both Mac and PC. ] Support guy sent a two page email with several steps to uninstall and reinstall; including clearing out preference files, etc. manually. Forty-five minutes of work. Opened; crashed just like before.