For me, around 35 lbs (in a soft case) is my limit. I did a private tutorial/clinic on a Tyros5-76 for several hours yesterday, and I must say, for the high quality of construction, and the excellent FSX 76-note keyboard action, it is a very reasonable 35 lbs or so in it's case.

If I was wanting/needing a 76'er for my work, I'd get one right away without hesitation.

Anything over 40-45 lbs is getting a bit on the heavy side, especially if the instrument is bulky.

I don't miss dragging a Rhodes around...it seemed to double in weight during a gig.

Ian