I like Viper. I've used it on the outside of my house for years. One application per year or every other year. Rain does not wash it away. Works well on my boat, too - once a year.
I typically hate using chemicals, but I haven't detected any adverse effects from Viper. I tried all the home remedies/non-chemical interventions first. They only worked in enclosed spaces. Bugs hate the smell of cedar. They also seem to hate the smell of drier sheets, but so do I. It's easier for me to spritz a bit of Viper around the ingress/egress that the bugs use. My annual application is at the end of the fall sailing season.