Lescott is a more than decent defender, who still has an important role to play this season. But Nastasic deserves to be the number 1 pick. At 19 and playing in a different country / league, he surely made his mark and is still learning.
I thought Mancini made a good decision to rest Nastasic in this X-mas fixture. Wish he'd done the same with Aguerro (in hindsight).