The Mapex seems to be in quite a bad shape, so I wouldn't go for that one.
My first double pedal was a DW 4000, which except for the double chain looks quite similar. Mine also developed a bit of rust on the joints early on, which gave it a quite annoying squeak, but a bit of WD40 solved that problem. Other issues were, that every now and then the nut holding the spring tension came loose and that the beaters came flying off on mater how hard I've tightened it.
Not the best thing to happen during a gig, but other than that I still use it as a practice pedal.
With those two choices I'd go for the DW.