I have not used it, but from what I have heard it is a higher level
way of solving problems with a high overhead.  The way you get in
trouble with such a tool is by trying to use it as if it were a low
level tool. You have to do things its way rather than trying to
bludgeon it to do things your particular way.

It is a similar problem to C programmers coming to java and trying to
translate their code line for line into Java.

I don't anything, of course, about that guy's situation, but I certainly
have my complaints about JSF.  I just said it's popular.  I think that
"popular" is quite an understatement, in fact, though the hype has
subsided in the last 9 months or so (whether from lower adoption or just
lesser novelty, I couldn't say).  Certainly there are serious
abstraction problems in the JSF framework, which the 1.2 release will go
a long way toward fixing but won't really get there.  Nevertheless, I
can't point to another web app framework that's not without its share of
problems.

It's also likely that Roedy's suggestion is accurate.  JSF is a rather
fundamentally different way of doing web applications, and if your
colleague is accustomed to doing things differently, he may find himself
at odds philosophically, rather than merely using a poor technology.  To
someone in the midst of things, it's often hard to tell the difference.