I am 5'6" and aprox 130 lbs, I purchased these in Navy, Charcoal, and Olive in a small and they fit as expected. They are tight like normal leggings, but not too tight that they are uncomfortable. I think if I would have purchased a medium I would be pulling them up all of the time. The material they are made of is somewhat thin, but not so thin that it's see-through. Length wise they are fine, they come right to my ankle with not a lot of extra material so I think anything over 5'7" this may end up being too short for you. I wear leggings a ton, I wear them on weekends, I wear them to and from work, I wear them as a base layer when its freezing outside...they are just about an everyday item for me and I would say these are quite comfortable. The tag states you should wash them in cold water and not tumble dry them, but I work full time and I have a toddler, I'm not doing separate loads of laundry for leggings so they go right in with everything else. I've been washing them on normal or the hot sanitary setting and drying them on high with no issues.
Now for the bad...
As I mentioned earlier, I purchased three of these in small from the same Amazon listing. For the navy and charcoal ones, the material at the very top is just regular stretchy material, the very top of the pants looks exactly how they are pictured in the Amazon listing and this style is often referred to as a yoga top (what I wanted...). The navy and charcoal ones give a normal smooth appearance where the waistband is and do not create any extra lumps or bumps that can be seen through other layers of clothing. The olive ones have the material loosely folded over the top with a very tight elastic band, which makes you look lumpy (think muffin top) underneath your other layers of clothing. The olive ones also just seem to fit differently. There's a lot more room in the front stomach area which combined with the super tight elastic makes your stomach look a little extra puffy, not smooth at all like the other two colors I received. So minus one point because as much as I like the first two ones I received, the olive ones just show me that you don't really know if you're going to receive the same leggings shown in the picture when you place your order.
**UPDATE 6+ months later***
First off, I'm happy that so many people found my review helpful, I make so many purchases based on reviews so I'm glad to help.
I liked these so much that I ended up buying a pair in black shortly after I left my original review. I have to admit these leggings with flip flops were 1/2 of my outfit almost every single day this summer, and they totally held up to the endless cycle of being worn, washed, repeat. They still hold their shape and have just the right amount of stretch, but they are starting to get thinner so you can just barely start seeing through them in certain spots like the front of my knee when my knee is bent. Given the amount of times they have been washed at this point, and given the fact that I wear them as pants, pajamas, and my toddler is constantly using them as a napkin, I am not deducting points for wear. I've even purchased more black ones, the light grey, and now pink.
I've also added a star back (still at 4 due to the mishap with the different olive ones) because I've realized that these are actually a pretty great value if you compare them to the other options on Amazon. If you look at most of the other cotton blend (not the poly spandex ones that have a slight sheen and usually look more like athletic wear), these ones are generally the lowest price.