It can be a close call whether to choose OW or *A, and I find it really depends on the places you really need/want to hit on the RTW and the class of service you decide to go for. I've done F and C on both, and neither is a hardship (as long as you avoid UA as much as possible).

I'm about to buy a RTW where I wanted to hit NRT, PEK, BKK and/or HKG, Italy, and South Africa. For optional spots, Israel would be nice.

An ex-Japan DONE4 ticket would be a great buy for such a trip. In January, I could fly NRT-BKK-HKG-JFK-BOS (where I live), then pop off for weekend trips to Aruba and San Francisco during the spring. Later in the year, I could fly to TLV via Amman, then stop in Rome, and then head won to JNB before returning to NRT via HKG. I'd be Platinum on AA by the time I got to JFK (using an AA codeshare on the CX flight), and I'd wind up with over 100k spendable miles.

Problem is, I'd prefer to fly in F. There's no F service to Amman, so I'd have to go to TLV via Heathrow, which really takes a lot of the fun out of flying up front. Also, the JNB-HKG sector is business-only at the time of year (Sept) that I'd want to fly.

So, I'm sticking with *A. I won't get to Israel, nor will I do the weekends in Aruba or San Francisco. But I will be able to fly to Florence or Bologna without having to change airports, and I will be flying in F on a bunch of good airlines: TG, SQ, LH, and LX; I'll also get to try F on Asiana. I'll fly a lot fewer miles (about 34000 instead of about 48000), but I'll get 3.0 or 3.25 redeemable LH miles for every mile flown in F.

In short, you likely won't go too far wrong either way; in fact, it's probably a good idea to see how the other half lives. SkyTeam, however, would seem to be a place to avoid, especially in F. While I'd like to try AF and Korean in F, the Skyteam RTW rules appear to charge you $100 every time you change a date or time of a reserved flight segment! Good grief.