They are good coins but they work totally different. You can't compare apples and oranges. Cardano is a 3rd generation blockchain and has much bigger potential than XLM imo. I would expect it to reach $10 this year.
Siacoin (SC) was pumped quite a lot but it's still a great project and on long-term, the price will be much higher than $1 IMO. I'm thinking of using it for backup storage for a project of mine, to test it out.
It's normal that there's a correction. Altcoins went gained a lot in the past few months and Bitcoin lost a lot of dominance. But I think the year 2018 will be the year of altcoins.
TRON (TRX) is still quite a new coin but it was way overhyped. It will take a while to reach new ATH. It's at a good price to buy atm, has strong support at $0.10.