We use it,..
just don't though would be my recommendation. We are currently looking else were for a system that appeals to the teachers and students alike. We recently found one good point about uniservity and that is the quiz/survey system is quite good. Unfortunatly you still regulary get timeouts and during a recent survey I have had to deal with a number of users who are having to constently refresh due to 'uniservity has encountered an error please refresh'.
Using basic html and creativity with the custom and hidden folders you can create some nice looking pages but this is somewhat more for the advanced user and require some nice graphics, being a photoshop power user the graphics part was easy for myself. The general over simplification of the system as a whole however I've found is enough to drive not only me (techie) but the teachers insane.
As a basic, basic system its not too bad depending on what you wish to do. Just dont expect anything amazing and certainly dont expect it to be quick,.. with one class using it for revision I must have nearly cut off suffolk from the www as the schools connection dropped to pre 14.4 days