I found the ending better on the second read. Once you get over the poor resolution to the prophecy, everything else is actually pretty good. Everything after King's Cross is awesome, and finished the series well. The epilogue is actually forgivable too I think. Admittedly it probably would have been better left out, but I think it was primarily to avoid fan-fiction...

As for the rest of the book, the camping was awful, and the planning section for the MoM was dull enough, so why it was repeated for Gringott's I don't know. Overall, probably weaker than the rest of the books, but as keeping the old (winning) formula was out of the question it was a good end to the series.