General consensus is that AA seems best for dealing with changes, etc. BA seems ok too from threads I've read.

I had a QF issued one and was one of the worst experiences I've ever had with an airline. They make it as difficult as possible to do anything with the ticket after it's issued. Never again! I'm structuring my next one to allow either AA or BA to ticket it. Which means I can't buy it from the OneWorld website again.

I also noticed that thing about the 34,000 mile limit the other day and posted about it in the Q&A thread. It seems like it's just poor wording on the site. There are two types of OneWorld RTW tickets, one is limited to 34,000 miles but the Explorer is not. The OneWorld site will in theory show pricing for both types and once you go over 34,000 miles flashes that error for the other type but I'm still getting pricing on an itinerary over 34,000 miles, initially even though that was the error I saw too, I think the real error was too many segments in Europe. The online tool is horrible for telling you where your error is at.

The ticket I have with QF was 49,000 miles, I did some pretty extreme routings with QR on that one since the middle east is considered Europe for that ticket, that was via the OneWorld online tool.