I have both a Wiim Mini and Pro. Both are excellent buys at the price, and even more impressive, are one of the easiest to set up streamers out there. They aren't perfect, but here's my evaluaton of the pros and cons.
Pros: great price, compact, one piece and far easier to setup and get working than many other players. Built in Burr-Brown PCM5121 is respectable, but it is easy to use with any external DAC that has coax or optical inputs (Mini supports optical only, Pro supports both.) Supports up to 24/192K streams. Allows connection to a wide number of streaming services. Has volume control and play/pause buttons on the device itself. Integrates with Amazon Alexa devices.
Cons: no USB output, no display option on the device itself and the supplied control software is quite basic and missing some desirable features (clear queue, add whole albums to a current playlist, etc.) but the software is periodically updated. Control software is currently iPhone, Mac OS, Android and Windows.