What are some alternatives?
When comparing Domainr and namegrep, you can also consider the following products
Agile Domain Search - Search great domain names for your website in seconds.
Wordoid - Wordoid is a web application which helps to solve a common problem
Instant Domain Search - Search domain names instantly by showing results as you type.
NameMesh - Get smart domain name suggestions using synonyms, suffixes, prefixes, short url, new gtlds to find the perfect domain name. Generate ideas for social user names and check availability for free!
Lean Domain Search - Find a Great Domain Name w/ twitter handle availability
Dock Name - Crowdsourced company naming ideas that help entrepreneurs find a domain name for their startup.