Average to excellent depending on version.
The cheaper (thinner rod) versions) made and assembled in Thailand where company based.
They manufacture higher end components as well and in Australia these are custom specc'ed and assembled and distributed by an Australian importer to customer requirements based on riders weight and riding style or race track use etc to set damping, rebound and spring rate range.
Parts on high end models are assembled in Australia. (piggyback gas etc ) but are probably made in Thailand too with stock spring rates.
Lots online/eBay etc sold out of Italy and YSS is now a major world supplier of motorcycle suspensions.
Quite a few on the forum have bought them so you should be able to search YSS on the forum and find reviews, commentrs etc.but like Progressive the range varies by quality and price.
The cheapest versions match or slightly exceed the Triumph stock versions but the middle and high level units (with thicker rods and wider body tubes etc), outperform the Triumph stock units by a comfortable margin.
Read the Aussie web site and google for more reviews etc.
Official YSS gear made to factory specification using the latest technology and parts. All genuine YSS products are sold with ISO and ABE certification from German regulation authority TUV. Buy world class suspension, buy real YSS products
yssaustralia.com.au