What PPC agencies do you use?

I've tried a few in the past, and there are also freelancers on sites like fiverr.com

Just curious, what PPC agencies have people had good (profitable) experiences with?

I've always relied on SEO and Google organic traffic but it takes on average a year to get regular sales to my sites that way. I'm interested in looking at more 'instant returns' with PPC.

I'm not interested in doing it myself, which I appreciate would be cheaper. This is partly because I don't have the time to optimise it but mostly because I'm crap at it, as has been proven several times.