In my personal experience, after being with Octopus for 9 months, they have been the best energy supplier I've ever used.
I haven't really needed to test their traditional customer service, I had an existing smart meter which they obtained meter readings from automatically from the first day of the switch without any intervention on my part. My first bill was a little bit delayed however they responded quickly to my email requesting this to be generated.
Where Octopus differ to most other energy suppliers is in their technical capabilities. Opening up new channels of communication via their API so that you can understand your consumption and prices at 30 minute intervals is very useful for keeping track of costs. Spurring a marketplace for 3rd party applications which can combine the use of the Tesla API with the Octopus API to ensure your car always charges at the cheapest available rates is something that I don't believe any other energy providers provide and personally, has saved me a lot of money.
On an environmental level, being able to understand when are good times and bad times to consume electricity to reduce carbon emissions is also I believe unique to Octopus.
No doubt they've had growing pains due to the huge interest in their tariffs and their unfortunately reliance on 3rd parties to install smart meters on their behalf. I don't dispute that some customers may not receive the experience they deserve but I do believe that there's no other UK company that offers the same level of integration or technical interaction with their customers.
I haven't researched how independent the Uswitch awards are but this year Octopus have won awards for; Best Customer Service, Best Online Experience, Easiest to Switch to and were runners up for best value for money. Which? awarded Octopus 'Utilities brand of the year' in 2019. There's a which review
here which states Octopus Energy came top out of 35 energy companies rated by 7,355 members of the public.
Finally, in terms of pricing, and the Agile tariff in particular, I don't think there's anything that can beat it. My average price for the last 12 months, in the South Scotland region are as follows:
Average all day Unit Price - 9.27p
Average of the cheapest 4 hours from each day - 4.62p
Average excluding peak (4pm-7pm) - 7.35p
Average peak (4pm-7pm) - 23.78p
Source:
Grafana