I had the same experience. I signed up but, when it came time to actually make a reservation I did some comparison shopping and found many cheaper alternatives. I think Homejoy's main challenge is simply the vast pool of available labor out there, much of which is also bonded and insured, like Homejoy, and that is already quite accessible to customers. The added layer of technological ease that Homejoy brought to the table was welcome, but ultimately not worth too much monetarily. For me, the real barrier to hiring a home cleaning service is the awkwardness and trust problems of having a stranger cleaning my house. And the technological mediation that Homejoy and similar services provide actually heighten this feeling of alienation, if anything.
To make matters worse, I then got an almost comically confrontational phone call from a Homejoy rep demanding to know why I hadn't completed my booking. This is probably an isolated case (maybe the rep was just having a bad day?), but it certainly didn't make me feel like I was missing out on much--all the more so since this experience was so at odds with the rest of the Homejoy brand.