Pros
Their positions usually pay a good starting wage for blue collar jobs in the given area. The company has no problems paying out training, travel, or overtime. Positions that work at a fixed location will usually have steady full-time hours, and on the road you can easily get as many OT hours as you want. They'll also issue boot vouchers a couple times a year if you need. If you're working as a laborer or CDL class B route driver, a position with CHES would probably come with a nice pay bump and they'll help you build some credentials like OSHA 40hr or tanker endorsements and so on. Career long haul class A truckers were probably some of the most respected and best paid workers in the company that I met on the Technical Services side.
Cons
You won't earn much PTO, and the base level counter with a 40 hour workweek seemed to tally up just under two workweeks off per year. Maybe you won't need sick days, but it is much more likely that you will never take a vacation. I think you get another week off after 15 years with them. The company covers a lot of ground and you may be expected to fill contractor roles a long, long commute from your home. In travel roles, you will be expected to spend most of your life on the road. People like to say that you don't need a college degree to do the job, and this is in fact true, but it is also because a workforce with a limited understanding of chemistry that doesn't fully appreciate their workplace hazards makes them more money. Look out for yourself -- this is a very dangerous job when you combine the driving, handling drums and other heavy stuff, and the chemical hazards.