The WBC is probably the most corrupt in its dealings with the minipulation of rankings... Usually has a good Champion though.

The WBA is a pile of Crap from Champion through to the 10th ranked.

The IBF is mixed in regards to its calibre of champion but its probabaly the most frequently vaccated belt and its mandatories are always rubbish.

The WBO is still suffering from lack of prestiege (relatively speaking of course ) but IMO does have alot of credible champions and contenders

The IBO is basically where the WBO was 15 years ago