Tube amps have wonderful detail and great dynamic expression.
Though those Twins probably aren't as heavy as this Traynor K4 I am using now. http://traynoramps.com/keyboard/product/k4/
But I like it as it has a 12" 2x4.5" and 2x2.5" speakers and 3 amplifiers so has a great sound range and you can switch it between tube and solid state preamp modes ... very cool. I always select the tube preamp as it adds a nice edge. But it does weigh 57 lbs ......

I am sure Ian you probably know Traynor as they are a long standing Canadian amplifier manufacturer. The K4 is a great keyboard amp though and is very suitable for a live rock band as it can cut through the mix which is what I need.