United lost my bags twice on my last trip to Europe. Once on the way there, and then again en route home. I don't know if that's their fault or not, but their staff pretty much sucked in response to my problem. Poor me.
I would agree that their planes are generally not as nice, and the perks in Biz class seem a bit less refined. I will avoid them on my next trip, based on my last experience, though I can't say I'd write them off for good.