This is awesome. I've used WITH RECURSIVE in postgres to do graph traversals (even replaced neo4j with postgres), and now this is also available with sqlite. I can see running tests in development becoming a whole lot easier.
Lots of us do this. If you're using an ORM then it makes sense to do it to keep unit test time down. We do it but have a full integration suite against the primary engine (SQL Server). Not had one discrepancy.
Your CI server should be running a stack very similar to production, but there are excellent reasons to use SQLite/H2/etc. in dev.
Being able to do a "git clone foo; cd foo; do my job" is a great way to start working, especially if you have struggled with front-end stylists using real data and back-end services, or any other specialised, possibly short-term, experts who are working on your project and don't have a need to learn basic db admin skills.
Never mind if you use RAC in production - you're going to make some concessions in your dev environment.
Yes, on the queries that I've done (mostly friendship graphs, and doing queries like getting friends of friends) postgres was pretty much on par with neo4j. I'm way more familiar with tuning postgres though, so there's that.
I really liked the cypher query language of neo4j, it was super easy to learn and is way simpler to express complex traversals across a graph. Writing a query in postgres to traverse a graph isn't as straightforward, and unless you're doing it often will take a long time to get used to.
The other exception I'd note is type-related stuff, since, while MySQL isn't always in line with the standard there, SQLite has deliberately chosen a different course than teh standard when it comes to types.
Fantastic news! My major gripe with SQLite was that it didn't support recursion (and subsequently had to move to a different database despite filling all of my other requirements); I'm glad to see this is no longer the case.
