Personally at this point, I'd avoid them. There are 3 well-known issues:
1. There is no communication, at all, at this point. A company that has a problem they are actually working on will communicate that, with estimated times for resolution. This company communicates nothing. They have a problem (no money), and they clearly have no plan in place to solve it. If they did have a plan, or even if they agreed this was an issue, they'd be communicating.
2. They aren't paying anywhere close to their posted pay dates, and in many cases reported here they are not paying at all. You will likely be working for free, and in many cases you will be spending your money on projects that require purchases with a high risk of never being reimbursed. If you take a project that requires you to spend $15 on a delivery purchase, you better really love that $15 item because you'll be paying it for yourself. Or...you'll be reimbursed 5 months later and you'd be much better off putting that $15 in your savings account that loaning it to Bestmark at zero interest.
3. They have a significant cashflow issue. They aren't having problems with their "new payment system". Thats hogwash. They don't have money to pay their contractors. It is that simple. A problem with the payment system doesn't get fixed for one month and then broken again for 3 months. Software doesn't work that way and no payment processor works that way (if they did, they'd be out of business). A company that is under-capitalized and doesn't have money to cover its payment obligations will do something like pay their bills/catch up, and then dodge all bills again for 3 months. Thats Bestmark.
Much better options out there.