I play MIDI accordion using the Ketron X4. I purchased it before the XD3 was available.

I have just purchased a petosa Millenium because my acoustic/MIDI Excelsior AC was a bit heavy as I stand when I play and I don't mix reeds with the MIDI voices when I play with the X4.

I have a set of JBL Eon 15G2's and Eon 10G2's. The Eon 15G2's weigh 46 lbs and if I remember the specs the Makies about 53 lbs. The JBL's aren't balanced as well to carry as the Makies but I wanted the lighter weight of the JBL's. Also the JBL's were several hundred dollars less than the Makies. I had an opportunity to do a cursory comparison of the 15 inch JBL's and the 15 inch Makies and found little difference. Those who have done a more in depth comparison may disagree.

I recently purchased the 10 inch JBL's because they only weigh 23 lbs. I play for senior citizen events and at long term care facilities and the 10 inch JBLs are very adequate for the smaller venues and for the variety of music I play. Although the 15 inch have more presence - even at low volumes.

I had Polytone Taurus Elite amps before the JBL Eon 15 G2's. The JBLs are by far superior in sound quality and frequency response. I expect the Mini Brutes would be inferior also.

To me the X4 and the accordion voices in the Millenium sound much better if run through a mixer - with no EQ on the mixer. I don't have expensive mixers either. Depending on whether I sing or not I use either a Fostex VM88, a Behringer UltraLink Pro or an Alesis Studio 12R.

I like to run the vocal into a mixer rather than through the X4. It seemed to get lost in the mix when run through the X4 and I couldn't control the balance as well. Now I am using a Helicon VoicePrism it is necessary to use a mixer.

Good luck!