I have used a bunch of different companies and I believe that constant upkeep and never allowing it to happen in the first place is the key. It may take a while, with treatment, to get rid of the problem that came with the house but once you get it under control, don't stop treating.
I also think self treatment is just as effective. And treatment around the perimiter outside of your home every two months or so is essential.
But I am too busy so we use Orkin. They come every other month and if you see anything in between they will come out for free.
Someone below suggested vaccumming well for the spiders. You must immediatly empty your vaccumm bag outside. The vibration of the vaccumm actually stimulates the spider eggs you sucked up into hatching!