There's quite a lot of choice if you're looking for a Z270 Micro-ATX motherboard. If you're prepared to pay big bucks, you should go for the ASUS Strix Z270G. It's a board that offers everything you'd want: a good power circuit, good audio, two M.2 slots (and even a heatsink that should help with heat dissipation) and SLI support. We're basically looking at an ATX board with the Micro-ATX form factor. In fact, the board even has features that are not present on the majority of ATX boards, such as the internal USB 3.1 header and the WLAN chip - although you will obviously benefit more from WLAN on a smaller board. Its average price is rather hefty though: £185. It receives an Ultimate Product Award, as it's the ultimate Z270 Micro-ATX motherboard.
The ASRock Z270M Extreme4 is also an excellent board, but it does lag behind the ASUS board in some areas. The power circuit has less phases and the MOSFET heatsinks have been mounted using push-pins, instead of screws. This is balanced out by the extremely good MOSFETs for the VCore, which will probably enable you to overclock decently. The ASRock board does not come with any extras such as WLAN or an internal USB 3.1 header, and two of its five fan headers do not support PWM, however the board is significantly cheaper than the ASUS board. Furthermore, the Extreme4 offers DTS Connect for its optical TOSLINK output, which ASUS does not. Its lower average price of £154 does not come with many lost features compared to the ASUS board. Therefore we award the ASRock Z270M Extreme4 with an Excellent Choice Award, due to its excellent price-performance ratio.
Lastly we have the two lower positioned models, namely the Gigabyte Z270M-D3H and the MSI Z270M Mortar. They lack SLI and USB 3.1 functionality and also have an older audio codec than the ones found on the ASRock and ASUS boards. They also have one M.2 slot less while also having a slightly worse power circuit. On the other hand, the MSI and Gigabyte boards are very power efficient, especially when idling, while being cheaper. The Gigabyte comes with an optical TOSLINK output, whereas the MSI board does not.
On the other hand the MSI board has a slightly better power circuit, with MOSFETs that are also found on high-end X99 boards, which are mounted with screws. The price difference with the well-priced ASRock Z270M Extreme4 is too small however to really recommend these cheaper models, but if you don't need the extra functionality while still wanting to overclock a little, you could consider these boards. We prefer the MSI Z270M Mortar out of the two, which is why it receives a Great Value Award.