Reporting/exporting is a challenge if you want to report on data across multiple campaigns. This may not be an issue for some, but for us we typically have multiple test campaigns set up in support of a particular project. We compile/aggregate results manually. We have to look up/export results campaign by campaign, which is time-consuming.
While the product, development/engineering, support and community folks at Optimizely are rock stars, their sales folks are not. Most of the people have impressed us in so many ways - so very customer-oriented, as Optimizely tends to be as a company/brand. However, from our perspective it's felt a little like the sales folks are not even part of the same organization. Very 'traditional' salesy. :(
We'd like to be able to set up multiple 'projects' in Optimizely for better/easier organization. However, each project requires its own code snippet for your site(s). This precludes us from creating multiple projects, and thus it's a little unwieldy in our interface. Also, since we have so many sites and campaigns, our code snippet is much larger than we would like. This again is a symptom of our own organization, where we have many, many sites (unlike many other companies).