LZF is conceptually very similar to LZ77. Generally speaking most modern compression algorithms give roughly the same compression, and with regard to the number of cores that you can use at once, it is up to you to decide how many you want to use. Generally speaking (unless you are creating large archives) there is no reason to need more than one though. In addition, with multiple cores doing the compression, the bottleneck may become the hard drive. Legacy zip compression is akin to the Deflate method in 7-zip, and will offer the most compatibility between different compression software.
