Him and Landon donavon last year at the emirates had the better of our full backs all game.
Sagna and Traore, I'd be worried if they couldn't, though Pienaar's goal came through the middle of the park and Arsenal played Denilson, Diaby, Traore = disaster.
Donovan is a very good player, every time I see him play, movement is good, passing is good, shooting is decent. Pienaar's I always feel has the right footballing brain, gets into the right places, the right idea's but his execution isn't particularly good.
Donovan was brilliant while at Everton, a quick check says he was player of the month in Jan when that game happened and Everton were a much better team while he was there.
http://www.statto.com/football/teams/everton/2009-2010/results
From when I guess he was there, early Jan through late Feb, look at how ridiculously improved Evertons results were. How they were early last season and how generally rubbish they've been this season.
He scored against Hull in March, so he was there for at least 9 league games, of which Everton won 6 games.
Pienaar average, Donovan really very very good, I'd never consider Pienaar for Arsenal, but I'd gladly bring in Donovan