Pros
I think there is a great culture on the development team - quarterly "hackaways", opportunity to open source projects, lots of sponsorship of community events (like the "3 day startup" in Austin). I highly respect management from my direct boss all the way to the CEO. Lots of advancement opportunity - a couple of employees come to mind who started at HomeAway fresh out of school who are now running large parts of the business, and there are lots of regular promotions.
Cons
HomeAway is a big company now - over 1000 employees worldwide. Also, since HomeAway was built by acquiring lots of small companies throughout the world, integration of all these parts and bureaucracy can be a major headache. I think management has a good handle on this (weekly "table talks", for example), but that doesn't mean that bureaucracy isn't still an issue. Also, it is the case that your fondness for HomeAway is most likely related to your immediate team, and given HomeAway's size there can be a lot of variation between teams. I've worked on some awesome teams, but I can also sympathize with those who have not been as fortunate as I have regarding their bosses and/or peers. If you are considering working for HomeAway, be sure to meet with your prospective manager and other people on the team.
