I signed up and paid the $1.89 for the trial. I use Oxylabs currently and was looking to try something new and possibly save some money. I found Soax via Google, but now I see they are here on the forum so I figured I would write my thoughts.
I only did the 3 day trial and didn't renew. However, that wasn't because I had a bad experience, but because I would need to change the proxies in all of my Multilogin profiles and that's a major task.
Soax proxies are really good. One thing that bugs me about Oxylabs and Luminati is that they use IPs from Cogent Communications in some areas, and Cogent is basically datacenter on a DSL modem. These Cogent IPs really suck and can lead to accounts hitting checkpoints. I asked Soak about their IPs and they sent me a screenshot that looked solid. All of the IPs I pulled were from solid ISPs and pretty fast. Same quality as you would get from Oxylabs and in some cases (in Denver, CO) better IPs.
I think the real selling point for Soak is that their pricing is the same as Oxylabs with a much smaller investment. Both Ocylabs and Luminati require a $300 p/m minimum commitment. Technically luminati has a pay as you go plan, but it's freakin expensive ($35/gb for city level residential). So Soax gives you the same $15/gb pricing as Oxylabs with only a $75 monthly commitment, perfect for noobs.
I like Oxylabs (except for those damn Cogent IPs) and my sales rep (Larry) is a good dude. They credited me on a massive data overage so I like that service. Plus, Oxylabs spent over 1 hour troubleshooting with me the other day, for an issue that was my stupid fault. So for now I'm staying with Oxylabs as my main provider. However, Soax is legit and the pricing is very solid. I would definitely recommend them for anyone just getting into the game and needing legit IPs for a low price.