Qemu is my tool for testing bootloader development as it is easy to drive from the commandline with options that fit your purpose. (Quickly add another disk, boot an ISO, or bootstrap a kernel/initrd)
VirtualBox I like because it is solid and easy to use even for advanced purposes. And it integrates well with RHEL/CentOS as it offers both 32bit and 64bit RPM packages (they could be advertised as CentOS compatible from the download section though). I mostly use VirtualBox for LiveCD's and other distributions.
Xen is too complex on my laptop and interferes with some of the things I do on the desktop. (hardware monitoring for one)
KVM is currently not up to speed on CentOS-5 (or RHEL5) because the KVM module currently available is old. This might change with RHEL 5.4 when Red Hat is finished with the recent KVM backport to RHEL5. By then I might replace Qemu by KVM.
I actually use both Qemu and
I actually use both Qemu and VirtualBox a lot.
Qemu is my tool for testing bootloader development as it is easy to drive from the commandline with options that fit your purpose. (Quickly add another disk, boot an ISO, or bootstrap a kernel/initrd)
VirtualBox I like because it is solid and easy to use even for advanced purposes. And it integrates well with RHEL/CentOS as it offers both 32bit and 64bit RPM packages (they could be advertised as CentOS compatible from the download section though). I mostly use VirtualBox for LiveCD's and other distributions.
Xen is too complex on my laptop and interferes with some of the things I do on the desktop. (hardware monitoring for one)
KVM is currently not up to speed on CentOS-5 (or RHEL5) because the KVM module currently available is old. This might change with RHEL 5.4 when Red Hat is finished with the recent KVM backport to RHEL5. By then I might replace Qemu by KVM.