Dutch company which exchange to use

was going to buy a dutch company but notice they trade on both the NASDAQ and Netherland market which is the best for a UK citizen to use.thanks

You probably want to research if there are any additional costs incurred for the NASDAQ listing, and if there are any tax differences on either side.

The value of the shares will be the same but in different currencies, the dividends withholding tax is the same (15%) regardless which market the shares are traded.
If the stocks in NASDAQ are ADR they may incur more some fees.
The remaining variable is future change of the exchange rate to the GBP.