Can't speak for YRC or ABF since their futures aren't very bright but it seems UPS will continue to be the flag bearer for the teamsters....and as long as UPS continues to turn a profit, the futures for the rest of the non-union companies will remain high.
I would much rather work for ABF than FedEx. Your health insurance pales in comparison and they pay nothing for it. Sure the pension fund is in some trouble but how about the non union companies that once had pensions and had it completely taken away for good? You can still make a good living at ABF and wages and benefits will be negotiated in the future. You get what FedEx wants and thats it.
As for YRC, they are victims of bad moves by execs at the worst time. But, if the union stood up and closed the doors instead of giving back in order to save the company, you would be all over the place preaching how unions close down companies.
But in the future if YRC fully bounces back, they will be by far the better place to work at.