For bass guitar I love it. Best amp I've ever played. Like it better than the GK's, Edens, etc. Now, I think the aluminum speakers are too bright, which is how I ended up with the Boogie cabinet. The combination does everything I could ask from a bass guitar. But damn if it just sucks with the piezo.
One thing I did that has helped is I ditched the 2x10 cabinet and plugged into a 1x15. The HPF got rid of about 75% of the nastiness and gave a much stronger input level. Changing over to the 15" speaker got rid of about 75% of what was left, so the net result is that it's not bad right now. Certainly not as good as I would like, but workable.