Bitcoin is the most popular and most common coin. But far from the most technological. Personally, I like Ethereum more. I do not understand the hype around bitcoin.
By the way, Ethereum is not much behind Bitcoin in terms of trading volume on this Coinsbit exchange. The trading pair ETH/USD has 17.6% of the total trading volume + ETH/BTC - 17.2%. A total of almost 35%. So here you can argue who is more popular than Bitcoin or Etherium.