Pros: Fun energetic sound
Cons: Nothing really for the price
Let's face it, you don't always want to take your best headphone equipment with you when you're out on the street. Sometimes you need a cheapish pair where it won't be a disaster if they're lost, stolen or damaged. I'm thinking particularly if you're going out to bars and clubs. I've lost many a pair of headphones this way (yes I'm learning my lesson...slowly).
If you're in the market for cheap supra-aural headphones you'd be hard pressed to look past Beyer's 501 p. The build quality is great and they're comfortable for extended listening (and I have sensitive ears when it comes to clamping force).
And to top it off Beyer offers a two year warranty on all their products (in accordance with EU law). I'm consistently shocked and amazed when headphones costing many times the price of these offer only a 1 year warranty (such as all of Grado's products).
I'm looking forward to the new Beyerdynamic Custom Street headphones that I think will even edge out these for price performance and value.