DaYan is one of the older puzzle brands, which was known for making flagship puzzles/speedcubes such as the GuHong and ZhanChi. Lately, DaYan has been making something of a comeback with the TengYun line being quite successful.
The recent DaYan ZhanChi Pro M 3x3 has also done well among intermediate level cubers, with positive feedback from most of them. The GuHong v3M and v4M 3x3s have also caught the eyes of many solvers and are a great attempt by the company at re-entering the cubing scene.
Apart from these, DaYan has also manufactured a 2x2 (TengYun) and Megaminx that perform very well. On an overall, they have made a good return to the market, and will always be remembered as one of the great cubing brands out there when the scene was still growing.