Like Matt said, they have a bad reputation. But, I have a black one that I bought from Freestyle, and it has been very effective for storing developer. The main thing is to make sure the cap is sealing properly. If you fill it w/ chemicals, smoosh it down, and find it has unaccordianed itself the next day, you have a problem. Cleaning it, well, that is a problem too. I run hot water in mine w/ dish washing soap and shake it like a banshee. Rinse, repeat, etc.
Any plastic container will retain some sort of chemical residue from absorption I would think, but would it be enough to make any difference? Considering the volume of chemical and what may be retained, I would think it's OK. Mine has been used for storing several types of developers, and it shows no signs of contaminating them. For fixer, I always use a dedicated container. I stressed over this sort of thing for a long time myself, even going to glass bottles and marbles at one point, which were a PITA. But reading that a lot of people just use regular old gallon water bottles for storing their chemicals made me decide that for the time periods I am storing stuff, there's no apparent problems.
My fixer is stored in one of those gallon brown bottles, also from Freestyle, and I squeeze it to keep air out of it. When I looked at the marking on the bottom, I noticed it has one of the less desirable ratings that is supposed to be not so good for storage. And yet I have a batch of Kodak Rapid Fixer in it that I mixed up way back in February. It always gets the old fixer dumped back into it, and what is in there now passes the clip test every time. I am going to throw it out and put a fresh batch in there soon because I am concerned about the silver content, but it has been great for storing fixer.
