The wikipedia article about LZ4 says that compression is slightly worse, compression speed is comparable, and decompression can be significantly slower compared to LZO. Can anyone enlighten me why I should not used LZO? I do not know anything about either algorithms, but if I switch from deflate I want to mak the right decision.
You misread that. It says that decompression is significantly faster than LZO. In fact, decompression speeds of up to 5 GB/s is one of the reasons LZ4 is so popular.