You can expect around the same output from both of them. They will both get a real opportunity to put up numbers with one playing alongside Olli and the other playing alongside Bert. I'd go with Stumpel factoring injuries.
I think I'm going to put my bid on Joe with a secondary bid (if first bid isn't successful) on Stumpel.
Really depends on what particular stats you are looking for. I run a 13 offensive stat league (Coolburn can atest to how deep my league is) with most of 600 players taken. If you're lookin for assists, power play points and faceoffs won, I'd go with Nieuwy. If you're lookin for straighht up points, I'd go with Stumpel playin the top line.