In any case, I would buy TRON since it has been very successful lately. Be sure to invest in Tether - it is the most promising stablecoin but in the future this may change slightly after the release of Libra. And of course the most important investment is bitcoin.
I dint think you should call any transaction in tether investment, tether is just a utility coin and not an investment coin, please tell me what the investment there in a coin that the value is constant and does not add value to its price. As the name implies which you confirmed yourself, tether coin is just a stable coin and that is al, you use it as pair for trade and you also use it to keep the value of your money, it will never increase in price for you to get any profit from it.
So, if you are using tether as investment, I guess you are really wasting your money, because whatever value you see in tether now is what you will see for the rest of their existence and your money will forever remain same in it. If you want to consider any coin to invest in, I would just advise you invest in BTC, ETH others.
