I have used several different e-commercie modules, including both PortalStore and Catalook, for DNN and so far have not found a "perfect" solution.  My personal choice is AspDotNetStorefront which is supposed to be coming out of beta next week.

It is a complex e-commerce suite and takes some getting used to, but the same can be said of the other e-commerce solutions as well.  The feature for me that is the real differentiator is the ability to easily add onto ASPDNSF through the use of their XmlPackage technology.  An XmlPackage is a simple method for packaging data queries, web queries and an XSLT into a single file which can generate just about any page or page fragment for display in the site.  I can add new capabilities to the system without requiring changes to the core tables or system.  In order to take advantage of XmlPackages you will need to learn XSLT, which I found took a little effort, but was well worth the investment.  XmlPackages addressed the problem that I quickly ran into with most other e-commerce packages I tried: what happens when your e-commerce site needs to do something a little different than what the vendor intended?  In PortalStore and Catalook I ended up writing a lot of custom code and altering the modules to suit my business needs which made it almost impossible to support module upgrades at that point.  With AspDotNetStorefront I am able to substitute standard XmlPackages with my own custom versions without touching the original package.  The system automatically detects that I have a custom version and uses the customized version instead of the standard package.

I do have to add that I do have a slight bias since I consulted in the conversion of the standalone ASPDNSF application to a set of DotNetNuke modules. 

Thanks for the replies, I'm trying to look at store modules that are already available for DNN. These should be mature products already (one would hope...).

It looks like CataLook and Portal Store are the only game in town? Are there any others that are already available?

Does anyone have any ideas of Catalook VS Portal Store? I've google'd for this and haven't come up with any real results.

It seems like the storefront is a pretty important part of many people's DNN sites. It seems odd to me that there are only a couple products out there already. eTailer, DotNetStorefront, AliCommerce, and the upcoming DNN Store Module 2.0 are all scheduled to be released soon. But a bird in the hand is worth two in the bush?