Well, the answer is, it depends...

As you increase the length of a horizontal loop, it will have lower angle lobes
that exhibit some slight gain on frequencies HIGHER than the fundamental
frequency. The gain might not be dramatic but the lower angle of radiation is
a plus.

For multiband operation, the inverted L is not recommended in most cases. On
its fundamental frequency, it is a nice, all around antenna since you get high
angle radiation from the horizontal portion and vertical, lower angle radiation
from the vertical section. However, depending on bands of operation, you can
get phase interference from the vertical and horizontal sections that might be
undesirable. Each situation is site specific and band specific.

What you will notice is that the horizontal loop will have 1-2 s units lower
noise than a vertical or inverted, based upon my empirical data collected over
a three year period with a vertical and loop in the same region.

Enjoy your antenna experiments.

73s,

Evan