Good for you.
I have a Polytune and my only other pedal need is a low gain OD with EQ options. To have a DI on that would be a bonus hence why the Tech 21 VT Bass covers so much ground. I'm going to stick with that.
More suited for the A string but the fix is simple - don't cut your A when installing new strings. The extra wraps help push the string down to get the angle needed at the nut.
I would agree with Danny - I still have the Blueberry but found the Spark Booster to have more definition for want of a better word. It does the low gain valve thing very well.