For a hobbyist, the biggest gain is the fun of learning something new.  I started (and still run) Langstroths in my backyard.  A couple of years ago, I added a top-bar and it's been a fascinating experiment.
 
The second-biggest advantage is cost.  A Langstroth costs about $200 to stand up (hive, stand, enough supers to have a harvest, frames, smoker, etc).  Your mileage may vary but regardless it will be out of reach for a poverty-stricken community like sub-Saharan Africa.  One of the key claims about a top-bar is that it can be made far more cheaply.  I was frankly skeptical of that claim and the first part of my experiment was to test it.  As it turned out, I made my top-bar for a grand total of $9 - plus the electricity to run the saw and some leftover screws in the toolbox.  The rest of my materials came from the neighbors' trash, including the glass that I installed along one side so I could watch the bees.  I 'splurged' only for the wood that would become the top-bars because I wanted some consistency there.  (A year later, I spent another $20 for a better outer cover but only because I didn't want to wait for trash day to roll around.) 
 Based on my results, the cost advantage was clearly and overwhelmingly confirmed.  A high-quality top-bar hive can be made out of basically trash for next to nothing.  And that's before the cost advantage of comb-honey only (that is, no extractor).
 
Add me to the list of those disagreeing with the statement that "Top bar hives cannot be inspected with any ease."  Once you get past the initial phase of drawing straight-ish comb and hardening off the edges, I find it far easier to inspect because only a few of the bees are disturbed at any one time.  I light a smoker for the Langstroth hives but never seem to need it for the top-bar.  And since it's on tall legs that put everything at an ideal counter-top height, it's far and away the easiest hive to work.
 
Disadvantages - They are harder to over-winter (in northeast Ohio) and I don't yet know why I keep losing queens.  But since it's all one big science experiment for me and my kids, even my failures are valuable and the ability to contrast two different styles of beekeeping is priceless.

Mike Rossander


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