My band has been doing some busking gigs this week (more on that in another thread soon), and we have really enjoyed using a pair of Traynor TVM50 amps. The battery supposedly lasts 8 hours, and they have enough headroom for guitar and vocals at the same time. Guitar and bass at the same time is slightly problematic, because when the bass hits a big note it eats up all the headroom and the guitar disappears, but you can't expect much from a battery-powered amp.
The microcube is great for playing outdoors. I actually only like one of the amp sims - the Marshall but it's a very good one. Doesn't sound a lot like a marshall but it's a great sound and what surprised me is how well it cleans up from the guitar volume especially with a strat. I also like to use a little chorus and reverb even though I never use effects in my band.
Ive been using the Crate Limo for many years. It sounds awesome, and the internal battery will power 2 channels for 6 hours. Then recharge, and go again.