Heard of them Don, don't like their fee structure personally, don't like it at all from what I have seen.
Volusion is another you may like to look at if you are considering Wigix. Having said that, I think the platform you have created at Bonanzle will be your most cost effective, try concentrating on driving traffic to that would be my advice.
I have seen others there say they are getting good results, but I am not finding it much use to me, but then again I am not really selling to retail customers, I'm selling bulk products to wholesale customers, so it's a different market all together.
I generate about 250 visits to my booth a day, on average, and I am finding that most are coming from b2b sites such as alibaba and tradekey.
I've just starting listing in wholesale directories around the internet, and that seems to be quite a popular way of finding me, and then I have a few locals from Bonanzle always looking for loads that they can use to stock their booths with.
It's definitely a site that requires heavy marketing, but in saying that it has a lot of members there all doing their best to bring in traffic, and when everyone is working toward the same gaol I think it has a pretty good chance of happening.
As for spreading yourself to thin, I think market coverage is an important strategy in any marketing plan, but the important key is to make sure all of your platforms are working to their maximum potential or you won't be making the most of your marketing efforts.
I'm also about to not only set up my own site, but also start marketing through ioffer, as they do have quite a strong traffic flow already established, and could be a good market for you to also look at if you're not already there.