Not a lot - he's wildly wrong on some things, not least the following - "Top Bars require more regular care and attention. Because the combs are foundationless, the bees may curve the comb on the bar, which causes problems down the road, including awkward comb attachments. Top Bar beekeepers tend to visit their hives more regularly to handle these and other issues. For a beginning beekeeper, the commitment can be a bit much" - herrumph! -in my view that shows ignorance about the usual methods of running a top bar hive - in my experience, most top bar owners choose not to "faff", and subject them to over-manipulation or intrusive and unnecessary inspections.
"You can alleviate this issue by harvesting and inspecting more frequently, which most Top Bar keepers do" - not any that I know of! Most top bar users will take the odd comb or two of honey as and when the bees can spare it, but certainly don't tend to inspect more frequently (or as intrusively)
"Other issues can include the inability to reuse wax" - so what? - to my mind using nice fresh wax is eminently more sensible, and far less of a disease risk.......
Less productive than a Langstroth? - certainly, "kenyan" Top bar hives really aren't designed to maximise honey production, but I don't view that as a drawback - as for the "size" criticism, don't faff about with a 3' hive, go for 4'!
Sorry, not a particularly accurate or erudite review...........hardly surprising as there is praise a'plenty for overpriced garish placcy beercoolers elsewhere on the site (and flogs them!)