Probably one of the first ones, i'm Test driving the 200 HP Diesel right now and will be until Friday.
If you expect BMW X3 Levels of refinement, look at the BMW. But if you consider the price, i think it's all right. Suspension is hard and can be a bit bumpy at times, but i don't mind it that much. Getting Sideways however upsets it a bit too much and it hits the bump stop - but who goes Sideways in a 200 HP SUV anyway

(And for what it's worth, the BMW does the same - Mazda and BMW can't just disable physics)
Quality wise in the interior it's on par with the BMW. Most definitely a class above what Mercedes does right now. Controls are an absolute joy to use and so on - but that's the same on the PHEV, so i won't go in to that detail. There's one thing i do not like as a Mercedes driver and that's the missing A/B (or rather "Since Start/Since Reset") trip computers. I do not like that it's burried in the central display and the function is extremely limited.
The Engine is superb. Yes, it has a bit of a Turbo Lag even with the 48V System, but the 6-Cylinder feeling is absolutely there. I just wish it had a bit more "bass" between 1500 and 2500 RPM. Transmission needs a bit of fine tuning, but it's not bad. There's a bit of jerkiness in some situations, but it's not knocking out your teeth. Overall, i very much like the 6-Cylinder with the Transmission. It also feels very "alive", as even though most torque converter automatics nowadays have clutches, they still can take some time to "go". (Granted, if you wan't ZF like shifts and responsiveness, your only choice is actually a ZF or a DSG, but that's because they have had years and years to tune the software and hydraulic clutch curves and so on)
I still have to do some high speed Autobahn driving (but that's mostly unimportant for every other country), Fuel Consumption is "okay-ish", haven't had the chance to do some real eco driving. Right now it says 5,8 l/100 km, but that's with quite a lot of idling and some very sporty driving.
What i am absolutely blown away by is the Interior Quality and how much you can throw this thing in to curves. Outside of Porsche and BMW, i never expected a SUV to like curves. It feels very "alive" - that may be a bad thing for those that seek a "cushy" driving experience, because it somehow animates you to drive. I've been using a lot of the driver assistance in the Mercedes - i don't really want to in the Mazda, because it's an absolute drivers car. The TCS is very liberal - it let's the back out quite often if you really step on it (especially as it's pretty cold right now here and the summer tires really don't work that great in these temps). The only downside is, that if the back steps out it get's a bit bumpy.
Seats are no where near the "full" Massage/Comfort seats in the BMW/Mercedes, but i don't think you can expect that with over 20k Euros in difference. The seats are okay though.
Some Videos:
(I'll be taking a few more)