The best bet is probably SS advocate, simply because there are so many potential clients.
Something like McKenzie Friends is probably necessary in the U.S. in order to provide low(er) cost, basic legal assistance. But it's got to be regulated, and the regs need to be enforced.
Here in CA we have a problem with "notarios", which are a common feature in Latin America but operate here without any oversight. They often have no legal training, don't carry malpractice insurance, and give out bad advice. In many cases they are simply practicing law without a license, and their clients get what they pay for.
I'd rather see that replaced with something like McKenzie Friends.