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@Tabe said, most of these are outdated. The YLM square-1 is still a fantastic puzzle though, but please spend the extra few bucks to get a magnetic one since its much better than the non-magnetic version. If you must get the Thunderclap 4x4, the mini one is better. For 4x4 I would recommend the Meilong M 4x4 since it has seen wide use in competition and has performance close to flagships like the Valk and GTS2. For 2x2 I would get the MGC v1 or Yupo v2. The MGC v1 is a better puzzle but if you can't afford it the Yupo v2 is still an excellent choice.