Is this bus easy to find and is it a good way to get to Bergen besides I imagine an expensive taxi or car hire?
We had no difficulty finding the bus stop at the airport that takes you into Bergen.
There's also a tram/light rail (Bybanen) that goes directly to the airport. https://en.visitbergen.com/visitor-information/travel-information/getting-here/to-bergen-by-plane/bergen-airport-flesland-to-bergen-city-center#:~:text=Bergen%20Light%20rail%20(Bybanen),NOK%2020%20for%20a%20child.
Yes - the Flybus is a great option. Comfortable, easy to find, and stops in multiple places in Bergen.
The tram is also a very good option. Whether the tram or bus is the best depends in my opinion which one stops the closest to your destination.
I took the Flybus from Bergen to the airport. The closest stop was one block from my hotel. Very easy and lets you off in front of the terminal.
Unless you have a lot of luggage, don't waste money on a taxi. Flybus or tram.
Note that the bus is four times as expensive (159 NOK) as the tram (40 NOK)