It all depends on traffic. The more traffic you get, the more your revenue is. I have seen a raw link astore of pr5 in this forum. I think he must be getting quite a lot of traffic. I understand that traffic and PR are two different things, but the efforts by the astore owner is well reflected in his pr rank. Must be doing a lot of article marketing or link building. With astore you don't have to spend anything except for some hosting space and or a domain name.
Build your own Amazon.com store is best - you customize it, use whatever language (PHP, Perl, Ruby, ASP, etc.) you want, interface with AWS, SEO it. You'll get free organic traffic. Do some PPC. You're set I never use AStore, BANS, etc. for any of my sites...
I have 2 astores and 2 AOM stores. The only profit I have seen from any of them is PPC so far. I am not being negative, just factual. I have not been selling from the four sites for long, and I plan to keep all four sites around for the next four years regardless of how the selling goes. I do want to start selling some products eventually.
Both of them are good tool but I think it's depend on how you gonna promote the site. More good traffic more income. I use blog and put Amazon products. Set tool auto post everyday. I want my shop to update all the time. Just start, don't even know the result yet. Hope, it's work.