Good grief. I can't choose and I don't want to. And I'm ever so happy I don't have to. I hope to see these guys on the Sox for a looooong time. They're ALL freaking bosses. I love how Eloy just plain mashes. And doesn't even pull the ball. He just murders it. Yoan is a great on D, and such a great refined hitter, while also being savagely dangerous. Robert does it all. His ABs are great appearance to appearance. For such a new, young hitter, he adjusts AB to AB. He is mashing without the benefit of even seeing fastballs. He steals bases with complete ease, and his speed will allow him to run out routine grounders. And he makes all the plays.
I certainly don't think the Sox have had such a dynamic trio, at least not that I can remember. They had lineups with great young hitters, with Maggs, Lee and Konerko basically all coming up together. Those guys obviously could all really really hit, but they weren't the rounded players (at least with Yoan and Robert -- maybe Eloy fits in well with this group.).
The closest I think is probably the early 90s, when they have Frank and Ventura come up basically together, along with Fernandez, Alvarez and Bere. Much different, but obviously some great talent there. The scary thing is, these guys could be better. Holy moly.