I would pay the $800.00, particularly if your RTW itinerary includes Asia-based airlines (CX, SQ--as their service is so great). You're going to be flying some very long hauls..Europe to Asia can be 14 hours or so. So, IMHO, if someone else were paying for C class & I had the opportunity to go First for $800, I would definitely pay the price; the difference in comfort and service is well worth it.