VEY interesting, but in Michigan, a secret ruling by the RAT attorney general (now our RAT govenor) has delcared these legal "assisted opening" knives to be illegal switchblades. Some out-of-state dealers know this, and won't sell to Michigan residents. Others will. If a cop asks you to empty your pockets, you could be in for a very nasty suprise when he slaps the cuffs on you.
Of course, Michigan has tons of secret laws, most of them quite stupid, that nobody but the police and prosecutors know about. They were promulgated by 40+ years of RAT attorneys general, who have acquired legislative and judicial powers on just their say-so.
I find AO knives to be interesting, but they tend to be of smaller and lighter construction than I prefer. There are some heavy-duty AOs, just like heavy-duty switchblades, but they're pricey. I prefer a more solid one-hand knife with secure opening and closing than an assisted-opener.