>>You may want to look at Lucene.NET - it's free and the search is excellent (and easy to incorporate into a .NET app).
>>
>>http://incubator.apache.org/lucene.net/
>
>Changing a search engine like that is not something that is easy to do. It requires a lot of preparation and it usually done once every 7 years, in my experience so far in this product. The policy is also to use, since the 2000, no third party at all. This allows the framework to be transported and scaled at any time. But, thanks for the reference

Yeah, understood - it's hard to justify switching if your existing solution works in most of the cases.

But realize it's open source so you get all of the source (if you want it) and can modify it as you'd like and has a reasonable license (unlike things like the GPL licenses), compile it in as part of your own solution, etc. Your other big "competitor", Stack Overflow was also running SQL Full Text Search and ended up switching to Lucene.NET (speed, reliability, configurability, etc.)