All these URL's go to the same place, they're just proxies. All the shares go to the same place, it is the same actual stratum or LP server.

The preferred IP is going to be minecnc.dontmine.me for both stratum and LP, but it can only survive small DDoS attacks before it gets null routed.

The first proxy service is through lb.izserv.com , how has that worked for people? I haven't been able to use it myself so I don't know (my miner is out of action right now).

The second proxy service is through cloudflare, but its longpoll/http only. It's probably the most reliable alternative, but I'm not sure how well it would stand up to a direct attack. It will also block some IP's automatically, so you might have to go to the http interface in your browser and clear your IP through captcha or something like that.