The Under Armour HeatGear Legging Bottoms fit snug but comfortably.  I purchased a size Large and I normally wear a "Large" in sweatpants and such, and they fit nicely.  They do show off every peak and valley of your bottom, your muscles, and other things, but if you're looking to buy a pair of these then you obviously already know that and either don't care, or you want to show off.  I have gotten a compliment or two about my backside while wearing these, so maybe it's not such a bad thing after all!

Like any other Under Armour product, you're paying a bit of a premium for the brand.  I've never felt an Under Armour purchase was wasted, but there are likely plenty of alternatives out there for cheaper if you really wanted to save a buck.  That said, I'm happy with the quality of this product, so maybe paying a little premium is worth it.

If you're looking for a full set of top and bottom, check out the Under Armour HeatGear Full T Tops.  I purchased both at the same time and they match quite nicely.