Thatonenoob posted a review of the Samson Z55 on Head-Fi. It competes with the ATH-M50/X iin the entry-level and portable use. Comparing to the M50, thatonenoob found that the Z55 was definitely more refined and smooth, and generally more agreeable with a wider array of genres.
Pros: SQ, Build Quality
Cons: Little Tight, Soundstage, Imaging