Mesh enclosures are thought of by many to be one of the best options, but saying for sure which is best is difficult because there are many people on here who're for and against them. I'm in the pro mesh camp because of how convenient they are in terms of the ventilation and cleanliness, however like almost anything there are drawbacks, some people report their lizards having claws pulled out by the mesh when climbing, and of course there is the frequent structural weakness of the mesh itself, but there are ways to negate such issues.
In regards to drainage there are various thread on here that have discussed and explored options to solving drainage issues in both mesh and non-mesh enclosures, I've seen some wonderful ideas on here. Are you a particularly handy person? I've seen small frames built to house drainage trays and all sorts.