1. IMO, the Global Explorer. A oneworld explorer (generally referred to as a OWE or a _ONE_, wherein the first _ is A, D, or L, depending on class, and the second _ is the number of continents) is a continent based fare. Your routing would be a five continent fare (North America, Europe, Asia, Southwest Pacific, and Africa). A global explorer is more of what you are familiar with in the Star Alliance because it's distance based. The prices are generally the same as a four continent OWE, irrespective of the actual number visited. The first and biz fares allow for 34,000 miles, which your itinerary appears to fit within unless you have a lot of sidetrips. An example is FRA-LON-JFK-SYD-BKK-HKG-JNB-LON-FRA is 32000 miles. The oneworld explorer would require a five continent. In first, an AOWE5 would be 10299 euro, and in biz a DONE5 would be 6599. With the global explorer, you're within the 34,000 mile limit, so a first would be 9099 euro and a biz would be 5899 euro.

3. Aadvantage, imo. It gives you the most bang for the buck when it comes to miles redemption. Status on a RTW isn't a biggie because you get the perks by virtue of being in an upper class (assuming you will be). Otherwise, I imagine that you're not going to deviate from the Star Alliance enough when it comes to your non-RTW flying to warrant making status a primary concern.

4. Not so well. It is more restrictive on a number of levels.

Keep in mind that all the Oneworld RTW products prohibit going the routing you originally proposed due to the South Africa trip. You will learn the quirks if you decide to do the trip. Although you didn't ask, whether I would recommend deviating from the Star Alliance is really dependent upon the type of trip you're looking to take and your reasons for deviating. The RTW offerings are just different. As I said, the GlobEx is closest to the Star RTW, but it is more restrictive, especially in terms of routing and the number of stops. That's why you don't hear much about the GlobEx on this board. Most people who post have done or do the ONE, because the ONE gives a lot more bang for the buck than the Star Alliance. Since it's sector based rather than mileage based, you can get a lot more out of it. It's not that difficult to get top tier on most of the OW airlines with one OWE trip, something that just simply won't happen on Star Alliance with any RTW other than with one of the smaller carriers or possibly LH. On the other hand, the OWE is a lot more restrictive in certain respects than the Star Alliance offering. If you want to set up an RTW that you visit 15 cities in Europe, one in Asia and one in North America, IIRC, the Star Alliance lets you. None of the OW offerings will. Now that you're probably thoroughly confused.