If you looked up whose linking to your competitors and asked for links from the same website.... Will the link be of less value because the linking site is already backlinking to a site that's competing for the same keywords and has similar products?
Nope, still good links to get. DOn't think to much about it, just different links from different sites, on differnet IPs slowelly does it.
find out first whether the competitor is ranked high on any specific keyword, then follow the backlinks. if a site is ranked high, then overall google likes its backlinks and you should be able to benefit by getting benefit from those sites. actually, this is the best way to get backlinks because you know links from those sites work. there might be some blog spams or objectionable links, but you will know when you see them.