We did it 10 days ago out of Gatwick and had no problems. We were staying overnight in airport hotel in order to make an early morning flight and were able to use "twilight check in" to be rid of bag the night before. I was concerned because I saw that by the smallest amount the wheels caught in that "sizer" though it fits wheels-in in the overhead compartment, but no one ever challenged me.
I was a bit apprehensive about this discount carrier with whom I had no previous experience, but all-in-all it was an entirely satisfactory experience. So, only issue some difficulty using/understanding website. Would consider future intra-continental travel with them. (Used EasyJet to make our itinerary an "open-jaws" one and EasyJet tickets were more than covered by UK departure tax on travel back to USA.)