I've always used booking.com and found the cheapest and also you get the 10%genius discount after booking more than twice. Well I think that's when they gave me the discount anyway
I’ve actually found the complete opposite. The price always seems the be the final price on booking.com whereas other sites apply tax etc at the end.
I've always found booking.com to be utter crap. When looking for hotels on comparison sites like Trivago, they always appear cheapest as they don't apply the tax until the final stages. Sites like expedia don't do this (to my knowledge). I always try to avoid booking.com for that reason.
Not worth the effort, tried this last year, it didn't track and the CS was abysmal
Not all accounts have this exact offer, some have a £15 for you and £15 for a friend who could work out better in some instances but worth checking