The Intel Core i5-4670K performed good enough for daily tasks, games, pi calculations, CPU benchmarks, and even encoding tests. It is clearly the best choice in its price range but is not worth upgrading to from a Core i5-3570K. It is the best choice for gamers as only few games take advantage of Hyper-Threading, and those that do don't exhibit a large enough performance boost to make the i7 worthwhile. It is important to mention that its integrated GPU is great for watching movies and playing less demanding games like League of Legends.
Its biggest disadvantage is not only the temperature but also its low overclocking potential. That said, if you find a good chip, it should still overclock to around 4.5 to 4.7 GHz, which is more than enough for most users, but we would love to see Haswell overclock higher.