I'm happy enough to stick with one of the 'big boys' (British Gas), even though I might pay a bit more. However Octopus Energy keeps winning awards, gets good reviews on TrustPilot and has been praised by ABers responding to similar questions on many occasions.
most of them do that, Bazile, maybe all of them. I've been switching at the end of the first year for a few years now. Ofgem actually write to me advising me to do so and listing some alternatives.
I've been with So Energy for a year, after leaving Bulb when their gas prices were stubbornly not following the downward trend.
Just renewed with So. Not the absolute cheapest for my usage, but very competitive nonetheless, bills are clear and accurate, and their response to queries has been exemplary. Also recommended by Which? website.