it’s fine and I use it for extremely performance-focused (see: linux gaming) and embedded systems, but LVM+ext4 is generally a better idea and I use ZFS for systems where extreme reliability and storage flexibility are important (so just my NAS machine really)

my response is halfway partly a shitpost (but only very partly)

if you're a general user, it's probably fine. if you're someone who cares about specific properties of things, it's probably less than ideal and something else would suit you better - but you'd probably already know that

some details: ext2 and ext3 had a lot of journal-damage/restoration issues, along with fairly severe density issues over much longer term use. the design characteristics also didn't lend itself well to higher performance (and this started showing a lot as the SSD age came around). ext4 has improved somewhat on the first and third parts, and soooorta has dealt with the second if you squint