I've used both and I think there is also a 60 watt. I own a 5 watt Microcube. One of my guitar players has just about every amp Roland makes for guitar and bass and he has given me several opportunities to test and critique. I like them all
. They all share the same electronics and emulation features, so basicly they all sound the same. The only real difference is the power. The 100 watt would be my choice strictly because it has 100 watts and it has enough power for a rehersal with other instruments and drums, thus making it a bit more versatile. The lower power versions sound just as good, they just have less juice. It depends on your needs.
I like every amp I've come across that says Roland on it
Rick