The mental issues are the worst in my opinion. Crippling depression, complete anhedonia, dwelling on every little thing that is bothering you in life and thinking its 100x worse...you know, that shit. Suprisngly it doesn't give me horrible anixety like some people will say, I get worse anxiety from a bad alcohol hangover. I never think I am dying or anything, but I might want to when its real bad. Thats the one major reason I have always been thankful for Suboxone...because even though it hardly touches some of the physical symptoms when you are at first switching over and tolerance is too high for suboxone to relieve it all, it still kind of numbs the psychological symptoms.
I would put insomnia as probably the 2nd worst, its basically a result of the RLS and restlessness. There is nothing better than finally getting some sleep when you are on a rattle...like 3 days without sleep and you are finally able to knock yourself out if you take some benzos and a few beers maybe a joint, too. Get like 4-6 hours of sleep and its like you come out of a tunnel on the other side and know things are starting to get better and only will improve from there. At least thats how all my cold turkeys have gone, but I wouldn't even deal with that BS anymore, at least do a rapid Sub detox or preferrably a 1-2 month Sub taper.