I think the varying opinions on the BP stem from a lack of predictable consistency, and set roles among the relievers, except for Kimbrel. Stat-wise, they appear very good on paper, but can't pass the eye test. For example, Thornburg did not give up a run, actually improved his ERA but it was a terrible performance. Many references made recently to Uehara, who I believe was not perfect (close to it) but was very consistent.
They also use a lot of pitches to get the job done limiting their ability to throw on consecutive days. The trend towards 5 and 6 inning starters also pressures the pen into many more appearances. Price's shutout effort yesterday was only good for 18 outs.