I am currently a Niemi owner (which feels fantastic). Neuvirth went undrafted. Our pool does not use daily/weekly/monthly transactions, just W x 2, SO x 3, total points count towards your team total at end of year. I also own Rinne and Halak, but having some solid depth as trade bait could be big.
We are only allowed 2 waiver pickups on the year, so they are nice to hold on to in case of injuries. However, with Varlamov still out, Neuvirth could be huge.
Going forward, does Neuvirth have a much greater prospect for W/SOs than Niemi by end of year? Enough to justify using a waiver pickup? What about Niitimaki?
2 waiver pickups is pretty strict, but I might do this. I can see why you'd be tempted. I think Neuvy will be huge, considering how much Varly was injured last year, and the problems he's had already. Neuvy will get you wins, I'm not sure about SO's, though.
I would think he'd have great trade value, but I'm not certain enough about the dynamics of your league to give a definite answer.
If shutouts are important(though they are in most leagues) I would probably hold on Niemi. I have him and don't like that I have him, but the common thread from what I've read from San Jose fans is that the team is so used to Nabokov that it's going to take them time to readjust to the new goaltending, and the extra rebounds.
I would take Neuvirth to the bank. Even if he ends up sharing time with Holtby/Varly, it still won't be to the extent that Niemi shares with Niitty, which could be 60/40 in Niitty's favour at this point.