I am curious to play with the text searching. I wonder how it stacks up to Lucerne or Solr in the text indexing space
If you are comparing them based on functionality and performance you are missing the point.
It is my opinion that this easily bests external implementations by reducing moving parts and removing the asynchronous nature of the updates to search indexes.
The text index is updated atomically and in real time. Best of all: it's not another part of your stack that needs to be setup and maintained.
tl;dr: use it, if a simple reverse index fits your needs, use Lucene for the grown-up stuff
> MongoDB text search is still in its infancy and we encourage you to try it out on your datasets. Many applications use both MongoDB and Solr/Lucene, but realize that there is still a feature gap. For some applications, the basic text search that we are introducing may be sufficient. As you get to know text search, you can determine when MongoDB has crossed the threshold for what you need.