They are very popular, especially based on price. However, they
normally do NOT meet specs, though they are sold with the claim that
they do. Often the 2nd harmonic of 2 meters is 10 db or more above
spec. QST found this in a test of one of the many versions.

An organization I know was planning on having some custom units made
up. After several weeks of going back and forth with the manufacturer
and not being able to get a straight answer, they gave up. At least
one picture from their spectrum analyzer was clearly doctored.


--
Alan
WA4SCA