IR (instant release) - Nice, solid boost of energy, confidence and moderate euphoria.
XR (time release) - 12 hour long anxiety attack with little 10 minute bursts of light euphoria every so often.
I took a 20mg XR the other day, and as quickly as I started feeling it, the feeling would go away and leave me with a comedown anxiety, then I'd feel it again, then anxiety, etc.. All day long....SUCKED!!! It made me reconsider my drug use altogether.
A few days later, a friend and I went for a late long walk, he crushed up the beads and we split a 20mg crushed up XR between 3 of us. That was a nice, clean boost of energy, no anxiety. Wore off easily, and I fell asleep no problem.