just read post #2 in this thread http://forum.fractalaudio.com/cab-lab-cab-lab-live/97115-06-ms-delay-trick-question.html so i get why the delay has a different effect on the sound.
I am experiencing the same. Sounds dull and lifeless when using CL3. When loaded into my AxeFx it sounds better. In fact I find the software to crash a lot too and I have to restart my AxeFx2 because the sound disappears. Very underwhelmed with it, I gotta say.
I think as shasha answered to me in another post when you use live mode the cab lab you bypass the cab block then when you send it to scratch pad you have all the things in the cab block added to it. I do not know if this is the real reason but It kinda makes sense I have started only using an amp alone when mixing cabs then building the preset. with this method for me anyways they sound the same when loaded in the axe.