Bob,
 
Here are some of the observations I have had since June in keeping
TBH's.
 
Benefits:
 
They are cheap to build and maintain.
No foundation.
No special frames.
No critiacl dimensions.
No storage problems due to supers and brood chambers.
Easy to move.
Ease of harvesting honey without opening but the smallest amount of
hive.
Adjustable hive volume all in one easy to build box
No heavy lifting and all the frames can be positioned at waist height.
Easy to cut and trim comb to fit or correct problems.
Easy to assemble with drywall screws and wood glue. No finger joints
needed.
 
 
Problems:
 
Being the top bars rest side by side they can be difficult to align due
to bees in crack and propolis build up.
 
Special rack needed to hold frames after they are removed from hive.
You can never set a frame down or lean it against the box.
 
Lots of roaches/spiders living in the unutalized back portion of the
box.  (I keep a movable divider in the hive to adjust the total amout of
hive voulume.)  "Central Florida "  Still waiting for the first snake.
 
More careful handling of comb due to no frame work for added support.
 
Tendency to build combs 90 degrees from the direction you want.  Be sure
to seed the top bar with wax and correct any problems early.  I try to
never add more than two empty top bars side by side.  I seperate the
brood or honey frames and mix in fresh combless topbars.  This helps
control comb direction.  I have the benefit of keeping my hives in my
back yard and can check them weekly if needed.
 
 
 
Note:
 
The hives I keep are 42" long.  10.5" at the base  16" at the top and
10.25" tall.  This give me about a 15 degree slope for the side and I
have very little comb attatchement to the wall and none to the bottom.
The hive holds 29 or 30 bars, each 18.5 wide with a .5 x .25 wood strip,
that I wax,  used to seed the center of the bar.  The enterance is at
one end and not the center.
 
I designed the hive to be build from standard 1" x 6" and 1" x 8" and 1"
x 12" lumber with minimual cutting and scrap.
 
Doing it again I would make the top bars 19" in length so that they
could be inserted into standard hives but that is a moot point being I
keep no Langstroth hives.
 
john wilkerson