The multi-carrier model isn't nearly as bad as you may have been led to believe. The primary distributors of the idea "multi-carriers hurt the business" are the exclusive carriers. By making you think multi-carrier is evil, it makes it easier for them to maintain their exclusivity with their drivers. You should always ask yourself this one question when you hear ANYTHING in this business: "Who benefits by this being the perception?" If it's the large/exclusive carriers, you have to AT LEAST consider the possibility that said perception has been circulated by the larger companies for their benefit. (For instance, while they are really awesome about not censoring people's opinions on here, this web site is owned and operated by exclusive carrier/s.)
The reality is, most multi-carriers aren't bidding against each other for the same truck because they use a completely different model of dispatching. Their primary competition are the exclusive carriers. They don't bid, then dispatch it to an available truck if they get it. They ask a truck if they would want it first, and if the truck says yes, they bid afterwards. I have never once had multiple carriers call me to ask if I'd be interested in the same load. And if they did, I'd just tell the 2nd carrier to call that I wasn't interested so that they wouldn't bid on it(IF it mattered. If both carriers paid a static rate, then you can tell them both yes, and take it from whoever gets it. Since you make the same rate regardless, it doesn't matter if one outbids the other. This is normally the case, in my experience. I've never worked with a multi-carrier that paid percentage instead of flat rate.)
Having worked in both the multi-carrier model and exclusive, there are less fees in the multi-carrier model from my experience, and you can stay working just as much, and quite possibly more in the multi-carrier model.
That said, I know nothing about this company, and it may absolutely be super shady. If interested in the multi-carrier model, I know of at least 2 good ones that I've never had any problems getting paid with, paid every week.