No airline is perfect, but Thomson seems to offer the best of both worlds in comparison to the 3 named airlines in this thread and Thomson are hiring again. Thomas Cook also offers similar mixed flying - another consideration.
If the contract situation could ever be figured out at Norwegian it could be appealing. Too bad they don't integrate the 787 and 737 flying like Thomson.
Norwegian is "supposed" to add as many as 30 A321LRs starting in 2018-2019 and that could offer interesting transatlantic flying - only time will tell if that happens and if they make improvements with their subpar contract.