Ask HN: Anyone try Direct Mail for B2B SaaS startup?

Has anyone given thoughts on using direct mail advertising for a SaaS startup? I am starting up a B2B company and it is pretty easy for me to get a list of companies' addresses that may be interested in my services.

I ask because I figure that a pamphlet or booklet in a colorful (or otherwise visually distinct) envelope would have higher open-rates than a cold email.