I support both. Bitcoin is the king of the market, all altcoins are affected by Bitcoin, Bitcoin is the most popular, and every day it has huge trading volume, it is capable of pumping up prices. For altcoin, I just chill out with high potential and valuable altcoins, because they have high growth potential. Currently there are a lot of altcoin not worth and they are scam, so I usually choose the altcoin located in the top 20 coinmarketcap.