2006: 0.92 ERA, 35 saves in 41 opportunities (85% success)
2007: 1.85 ERA, 37 saves in 40 opportunities (93% success)
2008: 2.34 ERA, 41 saves in 46 opportunities (89% success)
2009: 1.85 ERA, 38 saves in 41 opportunities (93% success)
2010: 1.80 ERA, 8 saves in 8 opportunities (100% success)
You can post all the Whip and K/BB patterns you want, but the bottom line is he delivers. He hasn't gotten worse the last few season. He was stellar in '09 and has been great so far this season. So his walks have gone up, but it isn't causing him to blow saves or give up more runs.
I think the fact that people have to use his increased WHIP and walks as his only flaw says a lot about how good he is. Yeah, he might not be as dominant as he was in 06/07, but you're talking semantics. He went from absolutely unhittable to extremely hard to hit. The point is, he is still the one of the top 3 closers in baseball, probably 2nd behind Rivera.
ORS:
To answer your question, yes, I'm as confident as ever in Papelbon. I don't expect him to strike out the side every time he goes to the mound, but I am just as confident in him shutting the door. He may get in jams every now and then, but he almost always manages to get out of them. So he blows a few a season, no one is untouchable, not even Rivera.