Essex was the 26th uni last year but dropped to 44th and dropped their over from bbb to ccc if you make it your firm choice, is Essex a good uni or just average
Last year it was voted University of the year from THE, and just like the rankings you quoted it doesn't really mean much. The University has a good atmosphere, the lecturers are nice and not afraid to explain stuff if you visit them, and the lectures are interesting. Although I suppose this all depends on your course choice.
My daughter just graduated from Essex last month and is returning in October to do her Master's. Her friend, who graduated last year, is also returning to do a Master's this October. They were both very satisfied with their choice of university but I would have to agree with what @AdamCor says, that it probably depends on your course choice.