I'd hang onto Evans, but barely.
I do agree that Bess is worth owning in PPR leagues but it seems he'll be fighting with Reggie Bush for receptions while Brandon Marshall gets his lion share in the Miami passing game.
Lee Evans tends to do the bulk of his fantasy impact towards the second half of the season and there's a decent chance that may be the case this season. It helps that his QB has improved from Fitzpatrick to Flacco as well.
14tm. PPR+IDP+return-yds. league
TE-Finley K & IDP-[streaming]