I have tried both as well as removal of glass for a 2x teleconverter to make it a auto stop down extension tube as well as macro close up lenses.
Macro close up lenses and extension tubes are very limiting in the range of focus so it limits composition and how the insect is photographed (can be too close up or too far depending on size of insect )
A teleconverter degrades the IQ a bit, but does not suffer from the same limitation of the former two.
It does suffer from light loss (hence flash power needs to go up )
I find that I like the Pentax Q7 with original PK adapter + macro lens to be my favorite.
There is no limitation on working distance and the pseudo crop factor works well.
With the original PK>Q adapter, flash sync can be above 1/250 too.
Taken with the Q7