Interesting. I've heard nothing bad about this one, as of yet, never tried it myself however.
Although batch scale rather than plant-scale, is my thing anyway, since I'm not working for the chinese (not that I would, given experience with fr.ex some of their hotplates and the likes)
As for N-isopropylamphetamine, I've never made it, but last I read it was something like 1/5th or less, of the potency of the primary amine. Massive drop in dopaminergic effects, so by the time one got anywhere at all with it, it'd probably cause so much in the way of peripheral side effects as to be absolutely horrendous.
Bugger that. N-ethylamphetamine on the other hand is actually quite nice stuff IMO, I prefer it to either amphetamine or meth (in either case, not street crap. although I've never had street meth, to my knowledge). Even the racemate, is a lot smoother a ride. Been itching to try the D-enantiomer, either via resolution of the racemate with chiral tartaric acid, or an enantiopure biosynthesis using Brevibacterium linens (limburger cheese 'red smear' bacterium, so cultures will be quite available, apparently up to 10-12g/l based on benzaldehyde can be tolerated. Not bad for a biosynth. And improved further if encapsulation either in alginate, or, so I've been told, mineral oil emulsions with a solid skin, is used.)