I see no reason to use uncompressed, other than for compatibility options. Either of these should produce the best quality file. Having said that, to maintain the maximum quality, I still recommend using one of the lossless compression options, and either native bit depth or 16bits. If you’re short on space, I would definitely consider using these, but be sure to keep a backup of your raw file. I did do a few quick tests and I can’t see any major compression artefacts, however they probably would become prominent if you start extensively editing the file. I haven’t done extensive testing to see the effects of the compression, as it would require a lot of testing on various different files, but I suspect it should be the equivalent to using a Jpeg file, but with extra headroom. Given that for a lot of people, the side of the DNG files when using X-Transformer was an issue, this could be a useful solution, if you are short on disk space. Bear in mind that the lossy compression results will change based on the contents of the file, and so this is just an example. I did a quick test using all of the options and here are the file sizes that I got. Just to clarify, in case there is any confusion, these options refer to compression in the resulting DNG file, and not the source RAF file.
