I visited this WHS in June 2017. Even though the area is quite big, it is not comparable to Ancient Merv. The different sites are a good example of how some of Uzbekistan's top WHS would look like without restoration. Moreover, the conical cap-like Islamic structures (top right photo) are in a way quite similar to Armenia's and Georgia's monasteries which I found quite striking. It's the mix of architectural styles and beliefs that I liked most in the ancient Khorezm capital as well as the fact that most remains are still believed to be sacred sites by the locals.
The absolute highlight of this WHS is the Mausoleum of Turabek Khanym. It is the largest building in ancient Konya Urgench and its dome holds an impressive mosaic of 365 interlocking geometric tiles that give the appearance of the night sky (top left photo). The number of magnificently preserved arches, niches and tiling suggests time keeping and calendar keeping was kept in mind when building this structure.
This is perhaps Turkmenistan's most important pilgrimage site and all pilgrims come to visit the Nadjm-ad-din Kubra Mausoleum (14th century). This mausoleum is quite similar to the Shah-i-Zinda complex in Samarkand, Uzbekistan but lacks the most of the magnificent turquoise and blue tiles on the mausoleum facades. However, the main tombstone inside has recently been fully restored and cleaned up to its former glory (bottom right photo).
The tallest structure is of course the minaret with its Zoroastrian symbols and Koranic script (bottom left photo). Restoration efforts were much better than the reconstruction attempts to the upper part of the minaret which is now leaning and possibly damaging the rest of the original structure which has so far withstood very strong earthquakes without any significant problem.
Overall, I'm glad I visited Turkmenistan's WHS as they helped me to better understand, appreciate and compare the restored WHS of Uzbekistan. That said, most probably I won't revisit Turkmenistan which has surely been one of the strangest places I've travelled to so far. So my suggestion is, if you have time allow 1 week max to experience the 'highlights' of this country but spend more time in Uzbekistan or Kazakhstan. I wouldn't recommend visiting Turkmenistan on its own as a country as its not worth it.