From what I've read from Valencia fans, the reason he's leaving Valencia is that he had a falling out with Marcelino and one of the reasons they stated that Neto wasn't happy that Marcelino was playing Jaume Doménech in the league during the final games in order to get him ready for the Copa Final.
When you read stuff like that you wonder why he wanted to come here. If Cillessen couldn't make a dent in trying to get the number 1 GK spot from Stegen, how could Neto? not that he's a bad keeper or anything but he won't be a starter here either.
Unless he's here for the wages and having Barcelona on your CV to go along with Juventus, Fiorentina, and Valencia is something to be proud of+winning trophies.