I have been using Domainface  since its launch. It does a few things really well:
- Saved Searches – You can save your search parameters and it will email you whenever a match appears.
- AutoBid/Snipe – If you link up your registrars, you can set it to bid at the last moment so you don’t signal interest in a domain (escalating its price) until a few moments before an expiring domain is closing its auction. I’ve won a dozen great domains this way.
- Domain Data – In one glance, it provides all sorts of useful data about expiring domains. How many links, indexes, Dmoz/Yahoo directory entries, etc.
- Integration with DomainSamurai – a nice Adobe-Air client interface to make it easy to discover related domains based on your keyword research.
- Search History – You can click on any searches you’ve done in the past and quickly find out if new expiring domains match the list.