Not sure why some think otherwise maybe because of his stature? However, Ospina is a quality keeper and has proved that at Nice and international level.
Before he joined us he was one of four keepers to save at least 80% of shots faced in the major European leagues, the others were Buffon, Navas & Neuer. At one point playing for us he had the 2nd highest most saves per goal ratio across Europe.
Also in his last season playing for Nice they conceded 0.83 goals when Ospina played which grew to 2.22 under their backups Lucas Veronese and Mouez Hassen.
I'd happily drop Cech for him and it's a blessing in disguise he gets to play now, he has superior reactions and is also a pretty good at saving penalties. I think he justifies his tag as the best #2 keeper in the PL but he could be a lot more than that if Wenger had faith in him IMO.
He really isn't, he's better than this washed up Cech easy.