Warwick's law does indeed have a diverse opinion.
On the one hand, general reputation amongst students and the rankings seem to indicate that Warwick's law is one of the best. However, on the other, the reputation amongst the legal profession is less than that of the mainstream universities.
One thing to bear in mind about Warwick, and especially for those who like to pride themselves in being a law student, is that Warwick does not have a proper law faculty unlike many universities. The law department is simply a floor (or two) on the social sciences building. Hardly impressive. What's more, I've been to the law library there and I wouldn't call it well-stocked to say the least.
One thing that may be of appeal to applicants is that Warwick tends to give out 2:1's and firsts far more easily than other universities - this goes to many subjects, and law is no different. I know a number of people at Warwick doing law who say that after a typical assessment (essays), 2:1's are the norm (rather than 2:2's at other unis). If grade inflation were an issue these days (which in my opinion, does not happen much with unis), it would seem that Warwick would be the chief perpetrator.