I love Vagrant. I’ve been using it as my development environment for several months now although I do still have to (reluctantly) boot up MAMP from time to time for older projects!
Eric Mann, a developer at 10up has recently made an Apache fork of 10ups Varying Vagrant Vagrants. The original VVV uses nginx which is cool, but seeing as how most projects we work with will end up in production on an Apache web server it makes sense to use this as my local development environment too. Especially considering that the main purpose of VVV is to allow developers to have the same environment in development as in production.
If you’re still using MAMP, don’t hesitate to jump on the Vagrant wagon. There is a TON of cool stuff you get with VVV.
There’s some more information about Vagrant and WordPress on Jeremy Felt’s site, go read http://jeremyfelt.com/code/2013/04/08/hi-wordpress-meet-vagrant/.