We are currently limited to unboxing and showing off Z390 motherboards; no performance reviews yet.  MSI's MEG was the queen of X399 motherboards so it will be interesting to see if they can replicate their success on the Z390 chipset. As you can see below there are a large amount of features; those metal shields cover the three M.2 ports with a U.2 hidden away as well, with the option to add another pair of M.2 with an adapter.  For PCIe you have four 16x slots as well as a 1x, so you know you are going to have a fair number of PCIe lanes available on the chip and motherboard. 

TechPowerUp has more in their preview here.

"MSI pulled out all the stops for their massive, EATX-sized MEG Z390 Godlike motherboard, which comes with three M.2 slots, full RGB support, and an adapter to add two more M.2 NVMe slots. You also get an OLED screen that can display pre-programmed stats and messages."

Here are some more Motherboard articles from around the web:

Motherboards