The main reason that Apple's switch to Intel was great for me was virtualisation. I mean, fast, multi-core OS X laptops and workstations rock, but the killer feature for me is that I can now use a Mac full-time, as if I need a Linux or Windows machine for a specific task, I can boot a virtual machine. And I love it. :)
Anyway, the main contender in the Mac virtualisation space has always been Parallels desktop, as this is the only mainstream, supported, final-release product available right now. I have to say, it's very good and I use it regularly for running Windows XP at work. Their Coherence mode was killer when it first came out too.
However, I have long been a fan of VMware for virtualisation. I make big use of VMware Workstation at work, and VMware Server all over the place (still can't believe that VMware Server is free!). We also do the full-fat, enterprise-grade VI3 stuff for a living, which is unbelievable if you've never seen it. For this reason, I've also been using VMware Fusion on my Mac, as I can painlessly boot up VMs that I've built on other VMware hosts.
VMware Fusion is still in Beta, but I prefer it to Parallels for four main reasons:
1 - It supports more guest Operating Systems (and has much better support for Linux).
2 - It has advanced features that Parallels does not (Virtual BIOS and 64-bit guest support amongst them).
3 - I use VMware elsewhere and like the easy portability of my Virtual Machines between Mac, Linux, Windows and ESX hosts.
4 - VMware Fusion is just more polished; the GUI transitions in Parallels are well-conceived but poorly executed, with jerks and ugliness, whereas in VMware they are simple and smooth. After a while, VMware just smacks of quality in ways that Parallels doesn't.
This week has seen some interesting developments; just as Parallels released Desktop 3.0, VMware have released Fusion Beta 4. Even more interestingly, Parallels 3.0 now supports snapshots (one of my previous gripes), and VMware now does Unity, which is like Coherence. Once again though, VMware show how this is done properly - Unity just does it so much better than Coherence (YouTube Video here).
As Jimbo said to me, it's entirely possible that we'd never have seen Unity if it hadn't been for Parallels and Coherence, and don't get me wrong - VMware Fusion is not perfect, but I am pretty confident that when we see a final release it will be the superior (and probably more expensive) option.
For now though, I'm continuing to use and enjoy both.
Update: My initial experience is that Unity does not work with a Vista or Linux; only with XP. :(
Also, check out this digg article for a whole load of comments that echo my opinion: "Parallels does it first, VMware does it right".
Also, Apple have released a fourth iPhone ad, which has me drooling even more than before. I mean, that thing is slick, right?!