The Vbox 4.1 release has got a major error: suspend on Linux host does not work as soon it is installed. So stay with 4.0 when you need suspend.
Phoronix: VirtualBox 4.1 Goes Gold
Less than a month after beta releases began, Oracle VM VirtualBox 4.1 has been officially been released. This is a major update to Oracle's virtualization platform they received from the 2010 acquisition of Sun Microsystems...
http://www.phoronix.com/vr.php?view=OTY4Ng
The Vbox 4.1 release has got a major error: suspend on Linux host does not work as soon it is installed. So stay with 4.0 when you need suspend.
Did not try that, i just reverted to 4.0