you might give swish-e a try, depending on the size of your project. it can handle lots of data, indexes pretty fast, searches as well quite speedy and its not too memory consuming. it is used e.g. on apache.org, and in our company (daily newspaper) we index ~ 250.000 documents with it.
downside: no incremental updates possible, but indexing is pretty fast (about 40 mins in our case), and it can handle multiple indices.

cheers m