Had the Amplifi 150w for a week and have just bought a MkII Shortboard over the MkII Express and for its added functionality, I'm glad I did. Found a tone I was looking for and am very happy with how it sounds.
That said, initial impressions were that this amp is average being used as a boom box, and the sound coming from songs played through the app are falling short of my expectations. If the app had a 10 band EQ on it, the sound may be tweaked to be suitable, but I am tempted to use the app for hunting tones alone, then playing along to my stereo.
The Bluetooth connection to the amp also drops out regularly which is completely annoying while using the app. Again, I'll only be using the app to hunt tones, then save them to my Shortboard and use the amp as a standalone piece of equipment.