I did LAX-IAH-FRA-CAI-LHR-IAH-PIT on UA and Egyptair on the Europe connections. I was Gold so E+ wasn't an issue but Egyptair is not really an experience I would repeat given the option. They spray the cabin with chemicals before landing in LHR which I definitely would not want to experience again. That LHR-IAH was my one and only op-up to J (and it was Xmas eve) so I do remember it a little more fondly than I would have otherwise.