TukUI mainly is a community, while tukui and elvui beeing two interfaces designed by TukUI team. Quite confusing, but what I said is completely right :P
Actually no. The UI you linked was ElvUI not TukUI and there's a big difference - ask anyone who has used them. While yes the TukUI website is a community both UI's are not designed by the same person. While both UI's are fairly similar they are both also very different, TukUI has very little in-game config and mostly requires LUA editing for changes whereas Elv offers a highly customizable in-game gui.