I am a backstreetboys fan many years now. The reason I like them and keep being their fan so many years its simply cause they are magnificent. Their voices are combined together so nice and the outcome is perfect. Each song they sing is a perfection.
When an artist makes an album people usually like 2-3 songs out of it, but with backstreetboys would be rare to find yourself not to like more the 1 song tops from each of their albums, that’s really something big!
They know how to follow the flow of music and they don’t stay fixed to one genre (they know what their fans would like to listen from them).
They are always original and always singing songs that can touch your heart.
If you are not a fan I am pretty sure you haven’t listen enough songs of them I am absolutely sure that you will find more then one song that will speak to your heart too.

“As long as there be music, we'll be coming back again” from Everybody(Backstreet's Back)
I really hope so ^^