Had a good chance to try it all out today... very very impressed.
The 1x15 is actually very good, and so so so light! Works well standing up and lying on its side, but not so good in the kick back configuration.
The horn control is good, can go from zingy to quite vintagey sounding.
The 2x10 is also very light, not sure if i'd be comfortable using it on its own, but with the 15 it works really nicely.
Putting both cabs on their side and stacking them is the best config i think.
Only bad point, the 1x15 has yellow piping, which looks ace, but the 2x10 has black piping, which ruins the effect.