I love adwords -----> adsense ........ It's probably one of the hardest to get going. But when you find a niche that works, the traffic is usually very constant compared to other sources.
I tried bidvertiser and all the clicks costed me an arm and a leg, moreover in some niches I wasn't able to trigger neither a single click
the bad thing about bidvertiser is that you can't target by keywords but you have to choose a category or a site and hope it brings you the visitors you want, hence not the best choice for arbitrage in my opinion
I agree with Icecube - bidvertiser would definitely be better if you could target by keywords.
I've not tried Adwords -> bidvertiser arbi, but like Adsense or anything else it could work if your traffic is cheap and you find a niche that pays well.