I started a similar thread few weeks back but had as much luck getting
some useful advice as you so far - just a few replies not really on
the subject - of what panel saw to buy? I see that there is a trend
here to suggest straight edge and rotary saw approach or track systems
like Festool or Eurekazone.
I have just bought the Eurekazone system and after spending some $500
for the saw and router attachments I see that the key (as I thought)
is the method of holding the 4x8 sheet and consistently making
perpendicular cuts. No straight edge or track system will provide that
- you need a panel saw - end of story.
For my shop the other key feature of the panel saw over the other
horizontal approach is the small space that is required to slice the
big panel. The vertical placement will save have of my shop floor
space.

As far as panel saw manufacturers I see two choices: Milwaukee or
Trax.
I think that both of them come to the same price of ~$2000 after you
include extensions to support 4x8 panels and dust collection. The
advantage of Trax is that it has router attachment and is powder
coated.
-Peter