I am purchasing a blue MX49 + gig bag from Frank.
Cons: Doesn't run on batteries, only 49 keys, no onboard speakers.
Pros: It has hundreds of cool sounds to noodle around on while on the go. I can see myself jamming with this keyboard while lying in bed or in the back yard, and using it as a sound bank at home while playing my 88-key digital piano or PSR-S970.
The Roland Go Piano is just a beginner piano - good for keeping up technique while traveling, but it only has a few dozen voices.
I might buy a lithium power supply so that I can play the MX49 away from an outlet.
Very excited to have a new toy.