I really wanted Capella at #17. He's exactly the mold of prospect you want mid-1st: unproven but high upside. He had really nice stats in euro play and has really nice tools, too.
I haven't watched Capella with the Rockets, but I will say that I haven't been very impressed with Young, and don't think he has much upside based on his physical limitations and bad D. So yes, I'd take Capella over Young.