The team at sales five has been great! They have helped us understand our business needs as well as given expert advise when it comes time to implement new features or functionality within SFDC.
I haven't found anything that i dislike so far but would like more options such as customizing email templates etc. If there were any issues we had they always responded quickly and fixed them right away without charging extra costs/time. This was my first experience using SFDC which made implementing very easy since all their tutorials are clear and concise.