I also have a bad back, degenerative disk disease, spondylolisthesis, and minor spina bifida occulta. I had a ex500 and a ninja 650r both were horrible to ride 1 hour tops and I wanted off then I got the zx14 and it was 100 times more comfortable it had me leaned forward more less pressure on lower back. I could actually ride about 130-150 miles before I had to get off and stretch. Now with the vision I can ride all day I rarely even get off the bike at gas stops I just fuel and go. To me my vision is like sitting in a recliner it is very comfy and handles great. The biggest thing is find what is comfortable for you not what is comfortable to someone on here or your buddy. Hit the dealers for test rides and demo days.