Pros: Easy Fit, Comfortable, Cheap, Sturdy
Cons: Relatively Short Cable, Casting
The JVC Marshmallows are in my opinion, a great low budget IEM. They are very user-friendly and the marshmallow tips are very comfortable in ear to the point where you can almost forget that they are even their. The sound is better than the standard earbuds you get with an iPod. The bass is pretty strong and the sound is decent for the price. The build quality on these IEMs are quite sturdy although the casting as bad with visible seamlines, the cable is quite good with little to no memory and microphonics are pretty low. They also come with 2 spare marshmallow tips. Isolation is pretty good (I use them in the bus and they isolate quite a good amound of chatter).
In all I think these are great for anyone on a really tight budget. Easy to use and pretty sturdy.