The product was recently introduced in Japan and it already has 11% of the market share there
There is not way to give a definitive answer to this question because different authors with different populations and with different methods fail to put their data in sufficiently comparable form so that the proper comparisons can be made

These may include: Global Blue Espaa SA (formerly European Tax Free Shopping Spain SA) Planet Payment Spain SAU (formerly Cashback and Premier Tax Free) Epay Taxfree (Innova Tax Free Spain S.L.) CaixaBank (formerly Caja de Ahorros y Pensiones de Barcelona) Open Refund SL Comercia Global Payments Entidad de Pago SL Financiera El Corte Ingls, EFC Travel Tax Free, SLU S21 TAX FREE, SL HISPANIA TAX FREE, SL B FreeTax Back SL Safety Tax Free Espaa, SL Wiblink, SL WOONIVERS SPAIN, SL (formerly Getrefund SL) Traveleasy GmBH Pucela Brain Storm, SL Yourtaxback, S.L. Upshop Tax Free Espaa, S.L. Pie Systems Spain, S.L. Revenir Remember that in Spain you can request a VAT refund on purchases in two ways: - At the airport or port when you are leaving the European Union and within a maximum period of three months from the date of purchase.- Through the Early Refund service offered by Global Blue and Planet within cities, tourists can request a refund in cash or by card in advance, before validation at the airport, providing a credit card as a guarantee and leaving the country within a maximum period of 15 days.

Oud Wood, however, is an all time favorite of mine
Totally different experience