I've seen some old complaints. They are the only ones I've found for the Taurus PT-99 and they are a good price.

They were recommended to me by Taurus.<ul><li><a href="http://www.mmcsight.com/">http://www.mmcsight.com/</a</li></ul>

Fact is, Trijicon makes about 80% of the market's tritium sights anyway so you might as well go right to the source.