I think most stats are a wash (SOG, FOW, PTS), but I'd side with Staal all day long...less injured and is his team's #1 center...Spezza will be a #2 in big-D.
Yahoo H2H - 14 GMs - 22 Player Roster - 8 KeepersG, A, P, +/-, PIM, PPP, SHP, GWG, FW, Hits, Blks, W, L, GAA, SA, SV%, SO
Giroux, Malkin, Ovechkin, Hall, MacKinnon, Letang, Holtby, Schneider
A lot of people doubt Spezza because of injury. Spezza is one of few current NHLers to be just over a point per game in his career. I like his opportunity in Dallas, and with FOW I'm holding on to him this season.
Dynasty League 1
Daily H2H - 16 Teams
4-C, 4-LW, 4-RW, 6-D, 2-G, 8- BNCH, 2-IR
G / A / PTS / PIMS / +/- / PPP / SOG / Hits+Blocks/ TOI
W / GAA / SV / SV%
I'm not a big fan of Spezza as he has burned me a few times whenever I have acquired him in my keeper league. Notable when I got Ryan and Spezza at my draft and I felt they were going to be the next amazing duo. But with him in dallas and assuming he'll play with Hemsky, who he had great chemistry with, he might be a nice player to have.
With that said, I like Neal a lot, and I have a feeling he is going to run with being the go to guy in Nashville. However at the moment the hype on Spezza is high while Neal is on the decline. If I were in your position, I would do a trade for Neal, but only if there is additional assets coming back your way. If not well, Spezza is a decent gamble.
Finally, I would stay clear of Staal. His point production has been steady declining with every season, and I suspect it to continue.