Hard to do an exact comparison, but I'd say he's similar to Alaba in a lot of aspects - fairly industrious, running almost non-stop, tall-ish for a fullback, quick in recovery despite sometimes over-committing in attack, and good on the ball in terms of passing and dribbling - though not as big of a difference maker in offense as the likes of Marcelo and Roberto Carlos in the past (Guerreiro from Dortmund is more likely to emerge as a potential matchwinner à la Marcelo) - and not as good a defender as Luís over the last half-decade. Since moving to Juventus, Sandro became a more efficient attacker and a better defender too - though his form has dipped a bit this season after emerging as one of the Top 3 leftbacks in club football in 2016/17. To get an idea of how effective he is in virtually all phases of the game when he's on form, here are a few Serie A statistics from last season:
All things considered he's a better footballer, defender and leftback than Rose, IMO. Put it this way: if non Premier League clubs were given the chance to sign Sandro/Rose - the overwhelming majority (if not all) would choose the former.