Cheap long haul flights have taken off over the last few years and I have had the chance to fly with two of them, Norwegian and WOW AIR in the last 12 months and to put it lightly, I LOVE EM!!! Sure they have pros and cons but they have allowed me to travel 10 times to the USA last year and without them, it wouldn't of been possible.
WOW Air is probably my least favourite out of the two. Mainly due to the stop over in Iceland which adds an extra couple of hours to a 7 to 8 hour flight. I found this the most annoying on the night flight back. You get settled, try and get some sleep, then 4 to 5 hours later, in the middle of the night you have wake up, move to the connecting flight and do the whole process again (i get grumpy when tired).