Pros: Seals like a champ, wide assortment of tips, abundant bass, well made cord
Cons: possible shrill upper mids
So, I've always used sealed or open back, over the ear, big boy headphones.
Tried a pair of garbage kinda-sorta-in-ear phones from best buy a couple years ago and hated every second of it. I was looking for something to wear on the subway that would both provide solid sound quality and wouldn't make my wallet sad if they fell apart after a year or so. I definitely found them.
For only 20 dollars, these are probably the best intro to canalphones I think you can find. The huge assortment of included tips not only ensure you'll find a pair that feel comfortable to you, but also help you learn what a bad, good, and great seal sound like.
As has been said, the low end on these things are remarkable. Likewise, at higher volumes, yeah, those upper mids could make you cringe, especially if you're used to really scooped out eq response headphones. This is, however, prior to burning them in. A little eq to bring down ~4-8 khz and these things are great even full blast. After a burn in I can only assume they'll sound even better.
The ear wire is fantastic. It really helps that seal from wriggling its way loose and seems like it really helps tone down the microphonics of the cable.
The way the plastic chunk that contains the driver and stuff fits in my ear is great. For me, it's super nice and snug, and inserting it feels super natural. I also really like that they have a sort of flat back, so I can just press flat against it to get a good seal.
At this price, I couldn't be happier. I'm excited to finally "get" in ear monitors.