I mean, they have things in common of course (Peru exposure, PM producers, good mgmt, growth stories) but on the other hand one is silver with 125m S/O and and one is gold with 175m S/O. Thing is, since the market (apparently) bottomed out they've been trading in a very tight price lockstep. Not percentage-wise, but real world penny-for-penny stuff.
Or maybe I'm reading too much into it.
disclosure: i own both but currently reco just one of them