The Boom line from UE has been my go-to portable speaker choice since they were first introduced. With up to 15 and 20 hours of battery life, respectively, they put out clean sound with plenty of volume. It's pretty easy to throw the Boom 2 in a backpack. The Megaboom 2 is a lot heftier, but oh-that-sound is so much bigger.
As with the Roll 2, you can connect multiple speakers together for a full stereo image. They claim a 100' range from your phone. In practice, this will depend on the thickness and composition of any walls that may be in the way. In other words, you may or may not be able to get sound from your room to the shower, even if it is within the range.
For the price the sound can't be beat. I love that the UE speakers come in a variety of colors; you can let your speakers reflect your taste.
