I think it's swings and roundabouts. TCB top up your cashback by maybe 1% (as a non-paying member - they have a premium account too like Quidco) and you can get extra bonuses on top of the payouts - I got an extra 5% by choosing to be paid in Amazon credit. Worth it in our house - my daughter's use it a fait bit and they pay me

. I also like how you can convert some cashback (up to £50) into Tesco Clubcard vouchers which I can then convert into 3 or 4x the value for days out, hotel stays and the like
I have re-instated my Quidco account but just as a basic member as I get cashback just from using my credit card in some high street shops but I originally packed them in due to some insurance payouts being refused - I was a bit cheesed off at the time
I prefer TCB's website and it seems to track pretty consistently and they have a guarantee to be the highest payer too .....
'15 Audi A3 Sportback SE CoD S-Tronic - 5+ year average 55+mpg
(Retired) '06 Honda FR-V 2.2 i-CTDi - Best/longest tank: 67.92mpg (+51.6%) / 815.5 miles.