No, not considered a peer of Patek, Audemars and Vacheron.
Probably in the next rank, although IMO not really quite equal to JLC or perhaps Breguet (Breguet and Blancpain are owned by the same , and I think Breguet is positioned in their marketing strategy a bit higher than Blancpain, though whether this translates into quality or marketplace perception is a different thing.) Certainly, Blancpains do not retain their value when compared to Patek or Lange, for example. They do, however, have some very elegant, simple designs.
Their motto is somthing like "We've never made a quartz watch, and we never will." Truth be told, this is because Blancpain was essentially a dormant brand during the rise of quartz watches and was revived in order to lend credibility to a line of mechanical watches during the '80's. It was probably the first really successful example of this strategy. Nowdays, there are all sorts of brands that attempt to trade on the name of a historical watchmaking company.