Well to start with it is really good n new start from moto by lenovo to work with modular features. They are also allowing third party skin makers to prepare skins as per requirement this is a good initiative but only worry is it should start at low price bracket as mid range phone buyers will be more interested in this.
Now talking about the phone, from X to Z many things have changed. 5.5 QHD amoled display coupled with SD 820 SoC says it all that it will be targetting premium users. 32& 64GB internal memory + 4GB RAM is also sufficient with expandable upto 2TB that too much. All this coupled with fingerprint scanner and C type Usb are really nice features to look in. Omitting 3.5mm jack will be a new trend for 2016 I guess and moto Z flaunts that. I am bit worried about battery back up as Z features just 2600 mAh battery though it has superAMOLED screen which uses less battery but 2600 is too less it should have had 3200-3500 mAH atleast. But I guess that will increase the phone thickness so moto has traded thickness over battery capacity. Tough moto is providing MoDs which can enhance your battery lets see how markets takes it up. Camera is also decent 13mp OIS and with Laser AF which is also of premium nature
In short this would be a very good buy if Moto MoDs makes good ground in market else battery should had been lil big to make it a hit as standalone piece. Still a good package to deal with.