I needed something of good quality and small dimensions, and the L-20R ticks both boxes. It looks like 3U but actually it's a bit bigger so you need a 4U space! Build quality and sound quality are good and it only records WAV files of channels that are activated, so if you record 4, you get 4 files, not 12 blank ones as well!
An iPad is essential. I had hoped the L-20R would record on its own once it was set up, but you need to connect to an iPad with the L-20 control app every time. (Things such as channel activation and panning are done on the iPad.) It is also not possible to group channels, e.g. pairs of mics, hence 3 stars for Features.
Overall it's a good unit and certainly ticks the ergonomic box but some future firmware updates would make it more or less unbeatable.