Was so excited about it opening and I still get excited about riding it. Although the tunnels are already notably less pristine, so I'm glad to have seen them when they almost sparkled.
That all said, at least according to google maps and citymapper the Eline seems to be a little situational.
For example, if you're on the Met line and want to go to Canary Wharf, it seems to not be worth changing at Farringdon to catch the Eline or even Liverpool Street, or even a cheeky Jubilee Switch at Finchley Road/Baker St then jump on at Bond Street.
Instead they recommend just doing the boring hop onto the Jubilee line and riding out on those numerous stops.
I tried manually calculating it and it seemed roughly correct, the long change times and less frequent journeys seem to mean it's still generally better to take the old routes.
But if you're already on the Eline it really is a blast across the city.
EDIT I suppose really the game changer was the connection to Paddington. I remember when Amazon moved from Slough to Holborn/Farringdon the transit was shockingly slow for the Reading crowd... the experience was bad enough people would Boris bike or Brompton it instead... I imagine it's even better now for any of the old Reading crowd who now work at Principal Place by Shoreditch