I just started playing with VMWare player 4.0.1, which was released in Nov 2011. It's pretty slick, and based on some lightweight benchmarks, computational performance loss turns out to be minimal. GUI performance is also quite good, and I conclude that using a VM to try out software or otherwise firewall your main machine from risky activities is a great idea with little downside.
Program installation was easy. VMWare requests that you create an account and give them an email before you can download. I found, however, that they do not check if the email is valid before letting you download the install image. Installation does leave a few VMware services running all the time, even if you are not running the player at all, but it's only about 15MB of overhead, so all in all it's tolerable, though I don't see why they can't just run those apps as needed.
OS installation was even easier. For supported OSes (I used winxp sp3) it knows how to automatically install the OS without any interaction from you. Just enter your license key, specify a few parameters (disk size, etc), and the rest of the install is completely unattended. Very nice for getting a good clean install of Windows for testing purposes, etc.
So to conclude, performance is very good - more than enough to use for all types of web browsing, and even compute-bound tasks. Though I did not test outside of Chome, I see little reason to think native apps would be distinctly different, though it is reasonable to wonder if GUI acceleration might be better outside the VM when using native (win32/.net) apps. Another test worth running would be 3d performance, should you want to run games in the VM. And, of course, it would be worth comparing all this to OpenBox, the other free VM out there. But with performance so good in VMware Player, I can't work up the motivation!
Finally, what are the resources consumed? Disk space is roughly one-to-one with the VM, since the disk image itself expands as you use more of the allocated space. There is also overhead for RAM hibernation, etc, but nothing very surprising. A bare install of XP + chrome took just under 4gb. RAM use is about 256MB above what you allocate to the VM (ie about 768MB on the host OS for 512MB given over to the VM).
Postscript: I did not try out the VM 2 HOST connectivity (shared files, clipboard, etc). It sounds like these are well supported, from what little I've read though.