According to James Ryley, Ph.D, President of http://www.freepatentsonline.com, patent search website http://freepatentsonline.com is much better than USPTO’s patent search engine.

1, Free (although lot of advertisements).

2, Free download of patent image in PDF format.

3, Fast search with these enhancements:

• Word Stemming
• Proximity Searching
• Search Term Weighting

4, Free RSS feeds with popular keywords.

5, Web site is developed using open source software including MySQL, PHP, Java and Apache HTTP server, Apache Lucene Search Engine.