I had the exact same predicament recently.
Revolut will win if you can lock in a good exchange rate, and don’t mind keeping the currency in your account for a while (it’s not going to fluctuate massively over a week or two… in general).
If it’s a case of… “I’m going away for a week… do I lock in the currency with Revolut first, or “wing” it with Starling”, I’d say wing it!
The ease of use, better support (in general), and the fact it’s your current account, rather than a pre paid account which might be used sparingly, is what made me choose Starling for my holiday.
Plus, if you haven’t already locked in the currency with Revolut before you travel, there is always a chance that by the time the foreign transactions are processed, the exchange rate might actually be better.
Although, realistically, it won’t be much better or much worse than the week before.