I'm tasked with choosing the fulltext search engine we're going to be using on an upcoming projects. Based on what I've read, I'm leaning toward Solr, but I'm a little concerned about spatial search. In addition to some other parameters (keywords, category, etc.) we want to be able to specify a location and a maximum distance (e.g., within 25 miles of Tempe, AZ). We'd like to be able to sort the results by distance.
Spatial SOLR is apparently pretty new, and it's not entirely clear what its maturity is. There are also a couple of other options (manually calculating and then inverting the distance, or solr-spatial-light.
My question is basically: is Spatial Solr (or solr-spatial-light) ready enough for primetime to handle the case I described above, or are we better off going with Sphinx?
I'd also be interested in hearing general experiences implementing either of these, particularly with php.