Check out the pignose amp I love mine I used the micro cube and the line six and the pignose is the best of them
I have a Roland Stereo MobileCube, a Pignose, a ZT Lunchbox, and a CB amp made by Joel Grey of GreyAmps in Chicago. Each of them brings something different to the party. I've also played the MicroCube and the Micro Spider. They each bring something different to the party.
So, if I absolutely had to choose, I'd choose the Roland. Why? My ears. I have played numerous guitars through a fair number of the Line 6 products, and something about them just doesn't sound right to my ears; I've even A/B'd them through Roland gear. The Line 6 amps sound a bit too sterile, even though I know many folks love 'em. Your ears might tell you something different.
If I was stranded on a desert island, and had to choose between those two, I'd choose the Line 6. The island being what it is (no electricity, except for the drinks ice maker), I'd need some place convenient to rest my tushy under a palm tree while plucking my CBG.