Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Nice for awhile, then edges curl.

We bought two, they were fabulous to stand on - really fabulous. But after about a year, the edges on all sides are curled up so much that guests trip and fall on them. Interesting that other reviewers note that Gelpro says this is unusual - we bought our two at different times from different places, and both are curling up severely at the edges. I would not recommend this product.