So what is a respectable OPS or WAR? Which numbers should impress me here?
For fWAR, wins over a replacement player, I tend to think of it as something like
1-2: meh, decent, beats a AAAA guy
3: pretty solid regular
5: really good regular, potential All-Star
7+: seriously great
This is roughly borne out by a look at the 2012 Nats
5.4 - Gio Gonzalez
5.4 - Ian Desmond
4.9 - Bryce Harper
4.5 - Ryan Zimmerman (WAR obviously doesn't know he was injured; in 2009-10 he was over 7 WAR per year)
1.9 - Roger Bernadina
1.8 - Ross Detwiler
For relievers, anything above 2.0 WAR is flat-out crazy awesome, like 8 WAR for position players or starters. Thus Craig Stammen = 0.8 WAR, Craig Kimbrel = 3.6 WAR.