I've only just started using the service to create logos and found it straightforward - very easy to use. Primarily I'm a coder/developer so visual is not my strength and this service gives me that edge to produce a nice looking logo that speaks to the brand.
I see some comments of the interface being somewhat basic, and I can see their point, but I think the tools are there for a little imagination to turn out something of quality.
What impressed me to even buy was the attendance of the co-founder to all the comments and reviews. That gives me confidence when a founder is actively involved with their service. And now that I've purchased and started to make use of Mojomox I'm quite satisfied and would easily recommend to anyone thinking about purchasing.