The new pricing seems reasonable, but I would like to know exactly what a "worker" is (e.g. is it a worker process, a thread, or a server?).
All in all, its possible to get up and running with a < 10GB shared SQL Server instance running a site with your own domain for $20/month. Seems like a pretty good deal to me.
AppHarbor is a multitenant platform and we're running multiple application on each application server. A worker is an actual worker process that is limited in terms of the amount of resources it can consume.
We'll add a more detailed explanation of what a worker actually is.