It all depends on which Javier Vazquez the Yankees get. I would lean towards the 2008 model, though not quite as bad. For reference, here are his past two years:
2008 (White Sox): 4.67 ERA, 1.32 WHIP, 3.28 K/BB, 8.6 K/9
2009 (Braves): 2.87 ERA, 1.03 WHIP, 5.41 K/BB, 9.8 K/9
He's going to be a good #3 and will be worth what the Yankees gave up. I don't think Melky is anything more than a fringe starter. Arodys Vizcaino may end up being the best player in this deal--he has great stuff.