I ordered for the first time from Abx a few days back, just before the trouble started. Marked my order complete, and then shortly after, the site went dark (attributable to DDoS, planned exit, whatever it'll end up being).
However, I've been placing orders through the post for a long time. Before there was a SR, before any DNMs, before there was BTC.
IMO, the concept of a DN marketplace, with forums, reviews, escrow, etc. is useful, to a degree, but also burdensome, perhaps more than it's worth. While it's good to have an intermediary between you and vendor, it's also another failure point, another risk of fund loss, another potential repository for your personal info.
I know that before there were actual DNM's, there were alternative means of facilitating deals. There was word of mouth, private sites, and even better, sites devoted simply to reviews only, no online transactions, no escrow, no middleman. Everyone could share experiences, get out the word on this or that vendor, and look out for one another. To some extent, reddit has become that service now.
I keep hearing about a new model, which would be a totally p2p market. I've seen mention of it here, and read a few tidbits on the clearnet. Seems like this might be a worthwhile evolution, but no system is perfect, and this assuredly will have flaws and limitations. People will always be lurking, looking for vulnerabilities and ways to game the system, and it'll be this way till the guberment wakes the fuck up and realizes what they're missing out on and brings all this shit out into the light of day.
Ultimately, I think the best position to be in is to build up a handful of trusted connections, and just DD it. That'll undoubtedly be an unpopular opinion here, now that the DNM Genie is out of the bottle. Nonetheless, I've had success with that approach for years and years. It's simple, and I like simple.
I am not going to abandon DNMs entirely, but if given a choice between trusting market intermediaries and keeping to DD's, I think I'd prefer to deal directly, provided I've worked through the vendor for a time. No matter what, if you do this long enough, you eventually get beat on occasion. Why not get beaten trying to make your order, instead of getting beaten by middlemen.
You can not do p2p market without multisig, if people do not learn multisig this can never happen.