Zap BI for Dynamics AX
Makes for very quick cube build and has XMLA built especially for AX. Not much work needs to be done for mapping or relationships. Zap support has always been very quick to respond and resolve issues. I have had a very positive working relationship with everyone I've met from Zap as company.
It would be nice to have some better insight to the CubeXpress product and how to make some tweaks for our own customization of our environment. It would be a nice feature to be able to view the MDX code behind the scenes.
I don't have anything specifically that i like least about the vendor.