ext4 has it's place - and deservedly so. But picking the right file system really depends on your requirements. For example if you're building a storage server then ZFS would be a better fit.
XFS is also worth taking notice of since the benchmarks I've read rate it for having faster read and write speeds than ext4. However I don't have extensive first hand experience running XFS (something which I'm currently addressing).
I've set up several hundred storage servers with XFS (up to 250 TB per FS) in the past 15 years. There were sour times, 10 years ago or more, but in recent times it's been rock solid and beat the crap out of other FS.
Notice that XFS always hated crappy hardware, because it pushes it to the limits.
I'm running XFS on a couple of my disks. It seems quick and reliable so far. My only complaint is that you can expand a volume (online, too), but you can't shrink it. Shrinking volumes comes in handy occasionally, and when you need it, you need it. But so far it hasn't bitten me yet.
XFS is also worth taking notice of since the benchmarks I've read rate it for having faster read and write speeds than ext4. However I don't have extensive first hand experience running XFS (something which I'm currently addressing).