I tried both side-by-side in the quiet "acoustic guitar" room at my local GC. I used the same guitar (Strat), same settings on the guitar, same patches in the amp. The 150 was noticeably more present and fuller sounding. Since I need this amp for gigs, I chose the 150. I loved the size and weight of the 75 and REALLY wanted it to work, but for gigs, I think the 150s the best choice. I'll gig with it tonight and let you know how it works.
mybalancenow.com