I would choose SD because the Hive community has reverse engineered code to render the SD graphics, but not the HD graphics.
So, tomorrow if the Reforged 2.0 servers shut down to spite us and there was no official way to play the game, my SD custom project could still be played with other people online and without cracked software of questionable legality, because we can render those SD graphics as their own game using a project like Warsmash
even if people don't use Warsmash because they don't like me, specifically. It's based off of "View in 3D" for Hive model downloader, and there are a bunch of other similar rendering programs, which themselves might likewise be used as game engines down the line.