Frenzy is nice, and thankfully legal. I've used lots of it and never had any problems. I've had a lot of good nights on exodus, however if you go overboard with Exodus, its not a nice feeling.
If anyone is using these i'd advise waiting for several hours after first having any to have more. And if its still working dont be tempted to swallow more to have a better night. Twistedness on a lot of these is not great in my books. And go easy on the water, enough to avoid dehydration is nessecary, but to much and the herbals will make you feel sick.
Ive never tried nemi though, i'll make an effort to give it a go.