Sins is different to Entrenchment in some ways. i usually only play Entrenchment, because there are many common features plus the new entrenchment stuff, however, original Sins has different maps, with different people playing online. the AI is also different to entrenchment (different features, ships, research etc) and entrenchment has 3 more unique artifacts. also, im not certain but its possible some number values are different (such as damage values, cost of research or resource income values, but dont quote me on that)