#1
I might buy a new amplifier, and the Vox Valvetronix series is my wise choise. Anywho, I'm still not sure if I should buy the AD30VT or the AD15VT. They are identical in functionality (only the AD30VT has got 'wattage control', dunno what is it, but probably useless) and the AD30VT has a 10 inch speaker, where the AD15VT has a 8 inch one.

I currently have a 15W Marshall MG (solid state) and when playing distorted I set the volume to a maximum of 15% of the total capacity.

Now, my question is, why should I buy the 30W version instead of the ?60,00 cheaper 15W?
#2
the wattage switch means you can turn the 30watt down to like 15 or something like that for playing at lower volumes or to use less power
#3
Will u be taking the amp gigging or is it just a practice amp?
My Gear:

Epi Les Paul Standard
Fender 48th Street Strat
Vox Valvetronix AD50VT
Martin Koa Acoustic
Some crappy unnamed bass
#4
U can lower the power and get better tones at lower volumes with the 30.
But id go with the 15 if u only use the mg at 15%. The 10 inch speaker would give better bass responce than the 8 tho...