Following is a posting similar to what I made on QRZ.com in reply to a guy who
was asking what kind of antenna to use out west in the mountains surrounded by
tall pines. It summarizes my recent experiences with a vertical on 80 m here
in central New Jersey:

Often you will hear the advice "Use a vertical. You will get the low angle of
radiation which you need for DX." Be very careful. Although this statement
may be true, you could still be disappointed, especially if you are surrounded
by trees, and being in the mountains, might have poor soil, which is necessary
for good vertical performance. I speak from experience. I have been building
and improving my 80 meter vertical recently, with disappointing results. It
is a full size quarter wave wire vertical, hung from a rope that goes from my
72 ft tower to a tree. I have 18 radials, 60 feet long. Now that is a pretty
good vertical, with no loading coils, with not very much that can be done to
improve it except maybe double the number of radials. I am located in central
New Jersey on sandy soil. I have used this antenna for the past several
weeks, mostly checking it out on DX. In no case has the vertical beaten out
the inverted vee at 60 feet. In nearly every case the antennas are virtually
identical. Even on DX to VK6 during CQWW this vertical should be kicking
major butt, but it is not. Ok, so a few days ago I modelled both antennas
with 4NEC2, and I made sure to include the appropriate parameters in the model
for my soil conditions (poor). And I overlaid both antenna patterns on the
same chart. Voila! There it is, the inverted vee beats the vertical at all
angles above 10 degrees, and is equal below 10 degrees. The moral of the
story, be careful about making assumptions regarding antenna performance
without having an A-B switch! And maybe the other lesson to be learned is how
meaningful the antenna modeling programs are.
So my conclusion is that even though the vertical might have the low angle
pattern, the losses in the soil do not allow the advantages to be realized.
Phased arrays of similar antennas over lossy soil may show the nice pattern
and f/b but the absolute value of gain expected may not be realized.

73 Rick K2XT