I think that Eth has way more potential and is much more interesting regarding what it can achieve through the blockchain.
It will probably be around for a longtime.
Altho, we've seen in the past (the http technology for instance) that the "best" tech is not always the most popular, and the one which develloppers/entrepreneurs use to build around.
So I'd say Bitcoin is the topdog for now, and will probably remain that way
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