I don't want to rag on Biyombo, who seems like a reasonably decent pick up at price, but here's a little perspective.
Per 36 stats
22-year-old Biyombo, 8.8 pts, 10.4 rebs, 2.9 blks.
23-year-old Olynyk, 15.6 pts, 7.7 rebs, 1 blk.
22-year-old Sullinger, 17.7 pts, 10.1 rebs, 1 blk.
25-year-old Zeller, 17.2 pts, 9.7 rebs, 1.1 blks.
Considering that Biyombo's rebounding number are likely at least a bit inflated due to his near total lack of an offensive burden and that I've never heard of him being anything to write home about on defense, I remain amazed at how people here can viciously rip Celtics players while remaining optimistically intrigued by clearly inferior players.
Mike