IMO, GABA-related sleep aids, either benzos or ambien, are definitely the most effective and invoke the least bad dream activity. I have read some studies that tolerance is more of a problem with short-acting benzos (and ambien), because you get a rebound anxiety effect as they clear out. I found this true with both ambien and halcion - I will usually wake-up after a few hours. I think its part of the rebound effect. Then you tend to want to take more, this is also truo especially for Xananx when used for anxiety. Mid-length benzos like Rivotril/Klonopin seem better due to lack of rebound, though you do risk that lethargic feeling the next day -- I drink 4-5 cups of coffee in the AM to get going. The really long acting benzos like Dalmane (and the infamous Rohypnol)never completely clear your system and you end up kind of zombified with chronic use. FYI - There is an informative anti-benzo web site in the UK: www.benzo.org.uk which has a lot of info about benzos and protocols for those who want to stop. Never go cold turkey after chronic benzo usage! As for me, right now Klonopin potentiated with DXM work fine and I haven't raised Klonopin dose in six months.