I have Pitlocks on three of my four bikes. Two of them are my highest value bikes, and the other is my lowest value bike. It's not so much value that drives my decision, but rather that I'd like to have everything still there when I come back to the bike. It's less of a pain in the @$$. Besides, I'd look silly riding the bus in full kit and a helmet.

The fourth bike doesn't get used for errands or commuting, so it doesn't need Pitlocks. Even so, it has bolt-ons instead of quick-releases.