Whenever I compared prices, SkyScanner hasn't been cheaper than Google Flights for me (domestic flights in the US and flights to Europe) and their website is much, much slower than Google Flights. Do you remember what kind of flights were cheaper?
SkyScanner is often either cheaper or more accurate than Google Flights.
Accurate: Google Flights often leaves out the mandatory "additionals" such as booking fee/credit card free, etc.
Cheaper: SkyScanner has more third party companies offering flights. This depends on which language/country you've set SkyScanner to. Try setting it to the country you're departing from. Flying from Amsterdam? Set it to Dutch! Suggest to try it now, sometimes difference is surprising. Though check out if that third party is trustworthy.
I often do e.g. a long trip (+flight) and then various short trips / flights after that. I book the first one early when on discount. The short ones much later.
