I flew them on round trips from BA to Mendoza, and to Iguazu last year in early April. Two of my flights were cancelled, but in each case, I was put onto a flight that departed around an hour later. No real problem, but fortunately, I had allowed for a 2.5 hour layover between my two trips, so being put on a later flight merely served to cut my layover in half between returning from Mendoza, and heading off to Iguazu.

I wouldn't recommend using Aerolineas with any sort of a tight layover.