I visited this WHS in March 2017. Having visited most of the 'beehive' sites on the list and knowing that the cost of this visit would be quite steep at 11 euros per person, I had low expectations.
Upon arriving at the Su Nuraxi parking lot, just outside the village of Barumini, I immediately spotted the highest nuragic structure and what seemed like circular structures which are quite similar to the ones of Choirokoitia in Cyprus. So to actually 'see' the site you can stroll by the street and view the nuragic site with the 15th century castle remains of Las Plassas in the background.
However, you'd be missing out on the very interesting guided walk through the nuragic complex and most importantly inside the nuragic 'fortress' which offers an unbeatable panoramic view of the whole site from the highest tower. Moreover, included in the entrance fee to this site are visits to Palazzo Zapata, which houses a limestone (whitish) nuraghe and several important remains found in Su Nuraxi and Centro Giovanni Lilliu which has an interesting collection of excavation photos and 3D models. The most important remain in Palazzo Zapata is the limestone model of a nuragic tower which was found in 'hut' 80 as it gives an idea of how the upper part of the towers must have looked like. It also helps to appreciate the signifance of the numbered basalt stones scattered around the site's perimeter which most probably belong to the uper parts of the towers.
The site bears no aesthetic beauty even though the surrounding green countryside in March is quite pleasant. However, compared to other similar sites on the list, this WHS is by far the most complete and the most important out of the over 7000 nuragic sites in Sardinia.
PS: bring sturdy shoes and comfortable clothes as you'll be climbing and crawling through some seriously narrow stairways and passages during your 1 hour guided visit. Visiting in the shoulder months also meant that we had a guide for ourselves and we were allowed to revisit and take photos alone after the guided visit. The UNESCO WHS inscription plaque is situated to your right once you enter through the wooden gate.