I would prefer someone more reliable as the 3rd choice CB at least for this season thou', just in case Bonucci is not as good as expected.
Someone whom we can trust to take up the starting CB role in that case...
Mexes is good, but wonder if he's willing to be a 3rd choice.
If the financial side of this deal is reasonable, I wouldn't mind him at all. In fact, I'd even prefer him over Gallas or Mexes, since they'll be asking for the moon.
Young and Serie A experience? Hmm, I wonder who that would be. Lets see... Kjaer taken, Bonucci taken. Ranocchia the next Nesta is left. He might be good.
But lets cast aside our mediocre notions and go for something a little more upscale to suit our needs... someone "young and Italian" instead of "infant Italian."