I find that dex is more speedier, with an uncomfortable edge to it, that rears its ugly head a lot sooner. The duration is a lot shorter and the comedown is horrendous compared with meth. I find it affects my joints/muscles more, with a real sapped feeling afterwards, even with proper nutrition/hydration/rest.
Like that ice age doco, where the group called themselves speed skaters, meth feels like your gliding through a smooth, euphoric stimulation. whereas dex feels like your downhill mountain biking, riding through a very bumpy, exhausting 'track'. It seems to go a little up and down after the plateau.
Meth feels very consistent and linear. I feel a lot more like myself, whereas dex puts on this energizer bunny bravado that turns me a little into a speed drone. Its like my brains been hijacked by a virus to work, work,work. Meth, i can take in the euphoria and stimulation and really enjoy the high it brings. I could work if i want, but i can just as easily be content sitting, twiddling my thumbs. Its versatile, and smooth. I feel like me in my perfect state. Me, but better.