I have two shops with EKM, I did have one of my shops on a self hosted wordpress solution for a bit. I'll be as unbiased as possible, but in my experience the customer service has been relatively good, e-mails answered at all times of day and all issues resolved so far and the forums are really helpful. I have some design/coding knowledge so it's been relatively easy to modify, the templates are highly customisable if you know what you're doing. EKM will do changes and custom designs for you at a cost, which is fair enough really, why should they do it for free?
They are lacking some (well, a lot) of features that I would really like, however it is only £20 a month for a fully hosted solution that works all the time and is easy to manage so there is a compromise.
I could see how people out grow EKM though, it doesn't have detailed stats, automatic follow up emails to prompt reviews etc, currently no mobile support (although it's coming soon) and there were loads of features of Jigoshop that I wanted to use and would love to see on EKM. I think it's perfectly capable of supporting a large and growing e-commerce business, and they do seem to keep adding updates and new features (despite a poor roll out of a recent new update, the update itself is great but it was very very buggy when first launched)
I think people are looking at it the wrong way a bit, it's a great solution and you can have a shop up and running within hours and it'll keep you going until you're getting possibly hundreds of orders a day, would it support the next ebuyer.com? no probably not, but it's only £20 a month.
It does what it says on the tin, if my shops get massive I might consider changing to get some of the features I crave. (check out betterbathrooms.com i love that site and wouldn't mind knowing what platform its on if anyone knows, obviously a custom high end solution) but for now EKM works well, is reliable and is very easy to manage.
Hope it helps.
