Gifgaff would be one of my 'brand loyalty' providers, solely because it's easy.
I can't think how long Ive been with them - perhaps even 10 years.
I have a £150 Motorola phone, which must be about 3 years old now, and £10 a month to Giffgaff.
I'm genuinely amazed by how much some people have...
Have Scottish Power use their area monopoly force you to sign into a sky-high 18 month fix rate.
Then claim £1,600 back from them once the term is over.
Bit niche I know, but it's worked for me!