How are they bad? I have not had an issue with them other than little things breaking, but that's what the warranty is for.
Well, the audio frequency on them is equal to that of a 25 dollar logitech headset, their cases are made out of China plastic and are incredibly unreliable. Their whole company is a scheme. They make a 30 dollar headset, slap a sticker on it, and put another 0 on the price tag.
Also, sennheisers are pretty stuffty to, while they may have good sound quality, their build is HORRID.