Id assume the H.O. has a better quality strip, layers, copper, etc... Everyone has said the regular strips felt under rated and could handle more with heatisink, so the H.O should have a better quality strip to handle an increased nominal power without external heatsink. If you want to push them to max then you will need sinks. From what I'm gathering these strips are basically rated at 2x the power of a regular strip so I would be willing to bet that each strip running at nominal power running without sinks would put off similar heat.
That being said ill have to check led count/specs to make sure there is no other difference between.. If that is the case you should calculate buying reguluar gen 3 strips and adding a quality heatsink vs the HO with heatsink... Only difference I can think of is a higher quality strip transferring the heat better to the sinks... So if H.O. with sinks can handle 2x power of a regular strip, I would assume a regular strip with sinks can handle 1.5x its rated max. Not sure I would want it running 2x its max as the core of the strip is probably inferior...
On a side note I am high and have had a few drinks. After all the posts I have read this is what makes logical sense to me but i obviously dont have both strips in front of me to confirm. That being said i wish I could put a few bucks towards a pot that runs these kind of tests for us vs all of us figuring it out on our own... way to much money wasted that way..
edited to add "dont have" instead of "have" towards the end
