As expected, Israel staged a diplomatic war against the deal, supporting the effort with claims from media sources, like in the Jane's Defence Weekly article that claimed those systems real destination was Iran (which was still under international sanctions and arms ban at the time), and that Syria is just playing an intermediary part in the deal. Other journalists and followers claimed the systems would end up in Hezbollah hands. Several Russian officials denied these claims.
Deliveries started before the first stages of the Syrian crisis in 2011 (some are reported back in 2007-2009). But by 2012 all 36 units were delivered. Judging by the delivery time, the systems are equipped with the UHF band, PESA target acquisition radars, with an up to 32km detection range.
Russia agreed to supply the second stage of the 2006 deal, especially after the rising tensions with Turkey and the few aerial incidents near the borders. These, unlike the first batch, were equipped with the more advanced AESA Target acquisition radars, with a range that can detect and track targets from 40km (wider ranges is reported, probably under ideal conditions), and a higher jamming resistance.
The older units were armed with 12 57E6-E short range SA missiles - export version -, with an average range of 20km ,we can confirm that all the older systems are armed with 12 from unofficial photos from the social media like this one .
Another incident is the December 2014 Israeli strikes on AA batteries near Damascus, the aggressors used Popeye cruise missiles (probably fired from F-15 strike fighters), this time we are sure the Pantsir was behind the failed strike, the location, pictures, and local media reports all point at this fact, but again, no further details are available.
special thanks to my friend Kane