Moving from OVO to EDF
I've just pulled the trigger on switching from OVO to EDF. I was pretty happy with OVO until they doubled the price of the unit rates for Charge Anytime but stayed with them because they were cheaper than Octopus for me and were the only one that offered smart charging that was compatible with my setup (I need daytime charging).
The last few months they've been hiking up my direct debit like crazy because their billing system doesn't take into account the Charge Anytime credits and their customer complaints procedure got me nowhere.
EDF are slightly cheaper than Octopus for me and they're currently running a refer a friend scheme where you can get £75 credit (if you use my link) and and an offer for £50 credit if you move to one of their EV tariffs plus £60 credit a year if you use their smart charge solution.