The Jonsbo UMX4 looks beautiful. The use of thick aluminum and glass are an excellent combination - especially as the chassis' top, front, and bottom are made out of a single piece of metal. In terms of overall looks, the UMX4 looks like a million bucks - or right on the money considering it goes for a bit more than 150 euros.
The inside may be a bit simple, but everything feels extremely sturdy - from the 3.5" HDD cage and PSU-mounting location to the sturdy motherboard tray. You may also install an ATX motherboard and fairly long GPUs. Jonsbo even goes as far as to enable the use of radiators with a length of up to 240 mm. But I would have loved to see the ceiling's mounting holes offset slightly for some more distance between the motherboard and a radiator to make the most of the available space. On the upside, there are three fans included right out of the box, and they cover all the essential areas.
There are a few small issues which are in stark contrast with the rest of the chassis. For one, there is no reason for why only select openings in the motherboard tray are equipped with grommets, or that the bottom dust filter is just a simple metal-mesh cover. It feels as though fixing these issues would not really add too much cost to the chassis overall while giving the user that elusive feeling of having paid for nearly uncompromising design on top of quality. Don't get me wrong, the Jonsbo UMX4 is a clean and sexy looking chassis with a mix of materials that demands a certain price tag; however, I would have loved them to go that extra mile to avoid a few small compromises.