One is third choice defender at the No. 1 ranked team in Europe, behind Rio Ferdinand and Nemanja Vidic, ahead of Phil Jones and Jonny Evans, previously ahead of John O'Shea and Wes Brown. The other is first choice defender at No. 4 ranked team in England, ahead of Laurent Koscielny, Johann Djorou and Sebastien Squillaci.
One is a Premier League Champion and European Cup Finalist after a 3 year top-flight career, the other is a one time Dutch Champion after an 8 year top flight career.
One of them was sought after by Sir Alex Ferguson and Arsene Wenger, the other was sought after by Arsene Wenger.
So who's better at the moment? I reckon it's Smalling, the kid's got everything, strong, fast, intelligent, composed, the next Rio Ferdinand basically. Vermaelen on the other hand is only better at goalscoring and has more experience, albeit mainly experiencing defeat.