The main problem is that there is no such thing as 'pla'. There are several hundred hundred different materials - all with different specifications and properties that are called 'pla'.

So while abs - is pretty much just abs - there are variations that warp less, have higher temperature usages etc - but compared to pla - damn few of them.

So while the pla you got 5-10 years ago was fairly limited - today you can get a pla based filament with just about any properties you like.
There are pla filaments that outperform abs in all properties. there are bendy pla's. hi-temp plas, conductive, carbon fibre reinforced.

So one thing to instantly dismiss when comparing abs and pla is the myth that pla is brittle, shatters or in any way weaker than abs. It's not, if you buy the right pla :-)

The main differences are fairly simple.
pros:
1) abs is cheap and has good mechanical properties.
2) you can use acetone to make it smooth and pretty.

cons:
1) unless printed in a fully heated enclosure - warps like a bastard.
2) you pretty much end up breathing in a lot of acetone fumes.
3) makes your workshop smell like burning plastic
4) can be tricky to make stick to print surfaces.

pla.
Pros:
1) very easy to print with, warping varies from none to a tiny amount.
2) will stick to just about any print surface
3) so many types around that there will be one that does what you want it to
4) good general prupose pla is cheap.
50 no real smell when printing.

cons:
1) specialist pla filaments can be pricey, although flexible pla is cheaper than tpu (polyurethane based) flexible filaments and much much easier to use

The point is that abs is a long standing plastic that was developed for injection moulding. Whereas todays pla filaments have been specifically developed just for 3d printing.