I've tried the Pure II and Duo in the past. Never in comparison with any of ALO's tube amps, though.
Still, if you want an amp that provides authority, a well-rounded sound, and an excellent tonality to boot, you can't really go wrong with any of the top amps from Vorzuge or ALO, to be frank. Personally, I've found tube amps like the CV3, CDM and CV5 to sound a little warmer in general to solid state amps, such as the Rx, National, Pure and Duo. In fact, I reckon you would be very happy with say, a CV5. This is an excellent choice if portability is a key factor.
For me, I pair my AK380 with either a Rx MK3-B+ or a Continental V3. Both are in heavy rotation (in fact, I tend to carry both with me wherever I go).
The CDM is a great amp, with a DAC function to boot. Still, if you're looking to get one, you're going to have to consider the cost, weight, size, and heat. These factors are all a level above those of the other top-notch portable amps on the market.