As for transparency, iZettle is definitely the better choice with all their few costs and fees shown on their website. Paymentsense requires talking to a sales rep for a quote. This is mostly because card fees vary between business types and monthly sales volumes, but also the kind of pricing structure you choose. The merchant account provider is likely to be Fiserv (previously First Data) who’s a partner of Paymentsense.
If you’re switching from a different card processor, Paymentsense promises to beat or match your current prices – and amazingly, they also offer to help with the cost of leaving an existing contract for theirs (this is not guaranteed, though).
iZettle has the same fee for all users, up until you sell for over £10k a month. At that level, you can negotiate better processing fees suitable for your business. At all times, you can just leave iZettle without consequences. Your fees are literally just the upfront card reader price, plus a 1.75% transaction fee for all card reader payments. If you don’t use it, you don’t pay anything. Refunds are also free, and chargebacks of up to £250 a month are free.
Paymentsense’s fees are capped throughout the entire contract, which can be good or bad. You’ll essentially be committing to the same fees for the duration of your contract without the option of lowering them if your business makes more money. However, you might feel safe knowing that Paymentsense wouldn’t raise fees during the contract period.
Both can accept American Express, iZettle for 1.75% per transaction, while Paymentsense offers it as an “optional” card to accept. Transaction fees will vary greatly between Paymentsense’s customers, but typically, Amex incurs premium transaction rates exceeding 3% for low-volume businesses.
Since Amex usually requires a special contract for acceptance, you can expect a setup fee for this. Again, iZettle does not charge you anything extra for taking Amex or any other international or premium cards.