1. Which provides more service: high street agents
2. Which is cheaper: online agents
3. Which gets the property owner a better price...
No one cares about 1 and 2. All that matters is the 'perception' of who can get the best price.
Until someone starts talking about who 'actually' gets the best price, no one outside of agency and journalism cares.
I, for one, won't be surprised to see this debate carry on with pointless mud-slinging from both sides (looking at you, Ed Mead).
P.S. The current crop of online agents don't have a technological advantage. There's certainly an opportunity to differentiate.