Firstly, as the app scales, livequery has to work harder and harder. I don't know how good its scalability is at the moment, but I think it would be very hard to approach the scalability of the feeds built into the database.
Secondly, as we build feed support into more and more queries, you'll be able to get functionality unavailable in livequery, which will allow building more sophisticated realtime experiences than currently possible.
We're going to find out how all these components work together in practice in the next few months. I'm really looking forward to that!
As for real reasons: - ReQL, functional, composable, and declarative, is very nice to use
- Changefeeds
- (v1.16) Arbitrary query watching with changefeeds
- Ease of sharding/load-balancing
- (v1.16) dynamic server management through queries
- Awesome web admin API
- Actually saving stuff to disk (couldn't resist)
This video on the highlights of rethinkdb is old but still relevant: https://www.youtube.com/watch?x-yt-ts=1422327029&x-yt-cl=848...
If I'm understanding correctly, RethinkDB could be a drop in replacement for mongodb? What are the benefits to this replacement in the context of Meteor?