They all work very well for social anxiety in my experience, which by now unfortunately is considerable.
Perhaps clonazepam is the best for social anxiety, but it is beset by supply issues and forgeries on the black market at present.
Clonazepam also has a nasty w/d profile.
If you're slurring, or worried about blacking out, your dose is FAR too high. Reduce by 50% - 75% or more. You should not even feel the least bit drowsy if your daytime dose is correct. Look up the correct medicinal doses for each benzo you are considering using, and start at the lowest point on the range. You dont want to be raising your tolerance prematurely and unnecessarily.
Also remember they are addictive as fuck., and most of them are awful to w/d from.
Drs keep banging the drums for SSRIs, apparently they do work for some people's social anxiety. And of course they are legal and far too easy to get a script for. Drs seem to almost be desperate to prescribe them. . I had about a 2 minute consultation, with 5 or 6 questions, for which it was obvious how i needed to answer to get the script, and I've been on Mirtazapine for years ever since. The Dr clearly did not give a fuck as he was reading the questions. It was very poor really.
The positives of mirtazapine are that it does help with sleep, and also the w/d profile is not meant to be as bad as many SSRIs. Mirtazapine is some kind of 'atypical tetracyclic antidepressant' w/e that means.. It gets its sedative effects from also being a potent anti-histamine.
It's emerging that the w/d profile of SSRIs and anti-depressants in general can be just as bad as benzos, so I genuinely feel conned and betrayed to have been put on the anti-depressant class of meds. As they were supposed to be a great leap forwards from the propblems of benzos. But they really arent imho. They have Never done Fuck All for my social anxiety either, and I've tried 3 different types. At least benzos work!
Of course the issue with benzos is tolerance, and potential dependence and addiction, although I've been using them for a few years without having increased my dose too much. (This time around. Which is my second time, after tapering off and quitting for 6 months a few years ago.)