The bookies might have City favourites against Madrid but City under Guardiola haven't proven to be a particularly effective team over two legs, where as Madrid obviously have in recent years. City just don't look the same team defensively either and, with Hazard coming back to full fitness, Bale with something to prove and perhaps a couple of additions in January, I reckon Madrid will have enough to see them through.
Atletico haven't been so great this season. They're still really suffering from losing Griezmann, Rodri, Godin, Luis Felipe and Lucas Hernandez, who they haven't really replaced in all honesty. They are 5th in La Liga and have dropped far more points than last season in games against the likes of Celta Vigo, Valladolid, Alaves, Granada, Sevilla, Sociedad and Villareal. Not the same, well organised outfit they once were and would fully expect Liverpool to go through.
The really interesting ones for me are Spurs vs Leipzig and Chelsea vs Bayern as both could really go either way.