I have been twice since they introduced the new seating allocation. The first time I was travelling with my dad, we did not opt to pay for seats and were seated together on both journeys. We flew back with relatives who had booked separate to us and they didn't pay either and they were also seated together.
More recently, I flew solo and opted to pay the £3 for an aisle seat.
All journeys were smooth and the seating was far better than what they used to have. I think it's better if people are called by row rather than just being told front or back, it is much quicker than waiting while people put their bags up