I would add only a few points to how using pkgsrc differs from pkg_add:

 * pkgsrc povides a centralized place to set some defaults.  E.g.,
   for printing, you can set a pkgsrc paper size variable.  Ideally,
   every package that supports print to different media should
   use this centrally-defined value as the default paper size.
   If you install precompiled binaries, you may well have to edit
   cofigurations for each package, manually.  (Or is pkg_add bright
   enough to handle this?)

 * If you keep your pkgsrc tree internally sane (e.g., never
   update just part of pkgsrc), then upgrading packages is relatively
   painless, even if a lot of interdependant packages need to be
   updated.  (Well, even if you only update pkgsrc as a whole, there
   are times when parts of it don't build...as you found out.  You
   can either update pkgsrc at that time---and possibly rebuild a
   LOT of other stuff---or go grab some precompiled binaries.)

 * If you mix pkgsrc with packages that someone else precompiled
   for you, things should generally be fine, other than possible
   defaults not being set the way that you want.  You may also run
   into version conflicts, unless you are building from the same
   version of pkgsrc as was used for the precompiled package.
   (Of course, if these come up, you can just update the affected
   packages, one way or another.  And, these may never come up anyway.)


The short answer, I think, is that you should be fine.  Depending on your
exact situation, the differences between pkgsrc builds & pkg_add should
tend to be small, subtle, & few---or perhaps even nonexisant.


  ``I probably don't know what I'm talking about.'' --rauch@math.rice.edu