Giffgaff
giffgaff: rolling goodybags, member support, O2 masts. Compare Tesco Mobile if you want Clubcard on the same host.
Pick Giffgaff for: O2 covers you and you want a flexible month.
About GiffgaffCompare
Giffgaff vs Smarty.
This is not a logo contest. giffgaff is O2. Smarty is Three. Check both coverage maps for your postcode. Only then pick the shop whose plan shape you like.
Smarty
Smarty: plain SIM-only on Three. Compare Three’s own shop if you want a handset, or iD Mobile if you buy at Currys.
Pick Smarty for: Three covers you and you want a straight data SIM.
About Smarty