At least not its datastore. It's extremely weird, hard to use correctly and nonstandard. You have to rewrite all of your data layer if you're going to move from it (or if Google will deprecate it, I think it will be quite soon).

I have very simple app there for personal use and I had lots of pain debugging it, and it still works on black magic. It's easy to rewrite that app from scratch because it's so small, but downloading data from datastore is extremely painful process involving browsing forums for third-party hacks. If you have more than few megabytes of data, I think you can't get it out at all.

Development tooling is also weird and glitchy.