Which coin gave you more return? Investment on Alts or ICOs or BTC? I have been holding BTC for a long time and I want to expand my portfolio. I have ETH holdings as well. I tried trading with many coins but never made of it. The reason I don't want to invest on alts is that those companies will create FOMO and make people buy and after buying you will be rekted.
If bitcoin is rising then altcoins rise faster than bitcoin in terms of percentage because they have lower price but it depends on total market capitalization as well. You can also choose to invest in ICOs because it has a possibility that it will rise more when listed in exchanges but the opposite may happen as well.
If the ICO has a holding period bonus then it would be better because there is a possibility that token holders would not dump their coins. If you want to be conservative then invest in bitcoin but if you want high risk but a possibility of having high rewards then investing in altcoins is good as well as long as they have good fundamentals.