Not tried the app version. Been using Fairemail for a while now, since k9 was unmaintained.
Fairemail is well maintained. Quick. Supports multiple accounts very well. Loads of features (could be a downside for those who like things simple). Designed with security and privacy as top priorities right from the start. Open source development. For a long time its been the best email client on Android IMHO.
Does anybody use Thunderbird on Android a.k.a. K-9
Just recently started using thunderbird to see how it would help managing múltiple Gmail accounts. Has anybody used the app version? Is it good? Bad?