Think XEM is good choise to invest.After catapult may be moon.
Obviously it is a quality project but i do not think that it has attained that level of adoption or usecases as big as ethereum or for that matter tron so if you are looking for alternatives these are my choices.
XEM is a good project that is still in the developing stage that will moon soon. If you have compared it with etheruem, you know etheruem is second largest cryptocurrency and XEM need little more time, is good for buy now before it starts the increase.