You don't go delirious from low doses (that's what hatman is). I still keep some for emergency reasons (I take much newer allergy meds), and if you take as prescribed you'll only feel mildly crap. Visuals start at much higher doses, but you will feel some interesting (but dysphoric) stuff at ~100 mg which is double the recommended dosage I think.

The only "valuable" part for me was seeing how good the brain is at making me experience stuff that never happened.
IMO it's interesting to experience once, and never again. There are far superior allergy meds, and likely sleeping meds too, as for deliriants I doubt any of them don't feel like shit.