lod @ 4 works fine for me , with 9 tiles of terrain at 128x128 vertices per terrain tile ,I get at max about
100 fps sometimes , if I switched to lod @ 0 ,I get max
about 13 fps .

using camera.lod and d3d_lodfactor I can make the
fps more constant and acceptable for real time rendering on my low end laptop .

and I guess from lod 2 to 4 would depend on how detailed the initial terrain is ,plus how far everything is
rendered .

I haven't experimental with shaders on the terrains yet
but I know shadows would plummet my performance
waaay down ,I think also that the algorithm for landscape lod does not quite keep the outline shape
of hills /slopes very much the same while reducing in
between ,well I think that's true ,not sure .

I havw to agree that gs terrain is not quite very good
if we had to look at comparison ,like esenthel wich
is able to run at a blistering acceptable speed on my
laptop with the simple and forward renderer .

anyhow my laptop is not the best thing to be using
for this in the first place but this forces me to
make use of all kinds of optimizations.