Anecdotal, but VirtualBox has always been a bit flaky for me. VMWare Fusion, on the other hand, powers the desktop environment I've used as a daily work machin

Anecdotal, but VirtualBox has always been a bit flaky for me. VMWare Fusion, on the other hand, powers the desktop environment I've used as a daily work machine for the last 6 months, and I've had absolutely zero problems other than trackpad scrolling getting emulated as mouse wheel events (making pixel-perfect scroll impossible). Despite that one annoyance, it's definitely worth paying for if you're using it for any serious or professional purpose.