It depends on whether you're in the dairy business. If you are, the consensus, developed over decades, is that the Yamaha 100 is the only way to go. It can easily lug two 100-kilo milk canisters, one on each side.
If you're not in the dairy business, the next thing to consider is if you will do any road racing, wheelies and donuts outside girls' colleges. If so, get a Honda CG-125.
For everyone else, there's the venerable Honda CD-70. Underpowered, underwhelming, and so ubiquitous, if
it ever gets stolen, take someone else's and no one will know the difference.