The Chroma is the exact same, but with colored paint. The Kraken has poor value for your money while the Corsair is one of the best headsets for the cost. Razer products generally have poor quality overall because you pay quite a bit for the Razer name. Definitely go for the H2100, it's the same as the 2000 and 2100, just updated in color from the 2100, which is just a black version of the 2000 with stronger swivel joints. The issue with the left speaker is very rare. The wireless is very nice, you won't notice a decrease in sound quality, but you could go for the H1500, which has the same speakers, mic, everything, it's just wired. The battery life is about 10 hours, and it stays that way for quite a while.
Razer has issues with quite a few things, the plastic is pretty cheap and can crack. The sound quality isn't great, it has a lot of bass, but almost no mid and the highs sound punchy. The mic is decent quality. The software is annoying to use and uses a relatively large amount of memory, can cause issues with other things.