I've found FreeBSD to be a nicer environment from a few aspects - better man pages than the GNU world and less SysV-vs-BSD cruft than Solaris. But my perspective is based on my experience as an operator rather than any big-picture considerations.
Granted I know I picked a random version (7.0 RC1), but the differences in maturity between the platforms is astonishing. This isn't a big deal when it's something that might at worst take rebooting to recover from (say, a SMP related crash), but with filesystems it's a little more crucial that they come through.
Sun never said that zones were the ultimate in virutalization - which is why they are coming out with XVM (their Xen implementation, basically).
I have made plenty of actual greenbacks with zones.
On the other hand, you didn't actually make any arguments here. All you did was assert that I'd never used the zones feature, make a point about something unrelated to zones, and then say that you made money with zones. Nobody is disputing that there is money to be made selling people Solaris instead of Linux.
I would at this point be more comfortable running applications under FreeBSD jails than zones, but, for obvious reasons, I would be much more comfortable running those same applications under virtualized Linux.
Zones are a useful tool because they provide the needed amount of separation (for me anyways) without a lot of overhead. They are portable to whatever the Solaris kernel is ported to (x86, x64, SPARC, and there is a PPC port being worked on).
A zone with /usr, /opt, etc. mounted read-only in the zone, is more secure (assuming no security holes to bypass the read-only property) than a non-zone Solaris system, yet it works exactly the same way. I can compile something in the global (root) zone and when installed under /usr it is available in every zone, and if there is a security hole that involves writing to e.g. /usr/bin/ping , it will fail.
Note that the kernel only loads one copy of each library, no matter how many programs reference or use it; this saves RAM compared to e.g. VMWare, and may reduce disk accesses if you have short lived processes as the library may already be loaded and resolved by the link editor.
You could duplicate this, of course, under any OS with a combination of NFS read-only mounts (loopback or over ethernet) and jails, although the administration overhead would be higher.
My reference to XVM (Sun's customized Xen) was to point out that if you don't like zones, you can still use "full" virtualization from Sun; it is not an either/or choice.
There are plenty of things that suck about Solaris -- zones aren't one of them.
Solaris Zones aren't virtualization. They're an isolation feature that tries to find all the shared kernel namespaces between applications to present the illusion of multiple machines. "Zoned" applications share a running kernel instance, and share a number of kernel namespaces that are not carefully isolated.
VMWare images do not share kernels. Their entire running state can be frozen and shipped across a network (or marshalled out to an iSCSI SAN) on demand.
I think Solaris Zones are a pretty crappy answer to "virtualization". It's basically just a stronger version of chroot. It's inferior to VMWare-style virtualization on security (all zones on a single Solaris instance are vulnerable to the same kernel flaws, and kernel flaws have been the majority of Solaris security issues over the past several years), and they're inferior on management and logistics.
* A security model that extends through the kernel
* A performance and resource sharing model that extends through the kernel
* Push-button migration
* Support for anything other than Solaris
* "Hardware"-level suspend/resume
* Centralized management
I can go on and on about the security implications of Zones (and Jails) --- I don't think this model is well thought-through. But on the feature-list alone, Zones (and Jails) are a pale shadow of what the "mainstream" OS's offer today.
I don't believe that most people need the suspend/resume/migration feature. If you have a cluster that can handle system failure then you can easily migrate a zone the same way you would deal with a failed system.
Anyway, I agree that VMWare/Xen offers important features for pausing and moving running applications. I use those features of VMWare every day. But, most people will do very well with Zones because they don't need and won't use and didn't learn and don't want to pay for the extra features that VMWare offers.
VMWare does not have this problem --- you need both a kernel fault (not rare) and a hypervisor fault (quite rare) to take over a whole VMWare server.
You can say "most people don't need" the features Zones don't offer, but I see my clients using them, and expect they'd mention them immediately if asked why they use VMWare.
Very few people will do well with Zones, because very few people still deploy Solaris. The choice between shelling out for Sun gear and shelling out for ESX is a no-brainer.