About safety, bitcoin is and next are the top tier altcoins on coinmarketcap.com. That's my basis for choosing and suggesting to others about altcoin and there are altcoins that are growing more than bitcoin does but they are all dependent to bitcoin market.
Binance coin.
If it's still earlier, I would go with binance but I don't think it's still a good choice.
May be it is a good choice for you but I am not agree to buy anything bu8t only bitcoin, it is high in price it is increasing day by day and for it is the surely that soon I will be safe and tension free for my future and I can enjoy the my present as it is safe as well as my future, investing bitcoin is making high level saving as it use to pump with every increasing investment and the more investors are now attracting towards bitcoin so my choice is going to be the one and only high potentiated bitcoin.