auto hubs are awful...
they unlock when you shift into reverse (whether you like it or not)
you have to be completely stopped to shift into 4wd.
they are weak and unreliable.

it is easy to swap- get aisins (what came stock on toyotas) they are more reliable than 99% of aftermarket brands

drawbacks- you have to get out and lock them... big deal.

some people will confuse automatic hubs with ADD- be prepared for that- THEY ARE NOT THE SAME!!