Welcome to FT!
One important factor in determining the best fit for you with regard to RTW travel is the nature of your
non-RTW travel patterns. Do you travel domestically or internationally? Are you a member or do you aspire to elite status in some frequent flyer program or another? This is the Oneworld board, and (I suspect) most of us agree that the Oneworld Explorer RTW product is the best one going. But it's not the
only one going, and there are some that are not as expensive as the OWE for travel started in N. America.
For example, Singapore Airlines (which is no slouch in business-class or higher service) has a RTW product all its own, that costs about $5300 if bought in the US. Limited destinations and nothing internal in the US, but you can do a fair amount of flying on your own nickel with the differential between that and a DONEx Oneworld RTW. Or, Singapore works with Air New Zealand and Virgin Atlantic to create the "Escapade" RTW, which allows for a lot more destinations than SQ alone, and costs $6800 if bought in the US. Miles flown on Singapore and Air NZ planes (but not Virgin) would accrue to a United Airlines mileage account, so if you're a UA member that would be a real boon.
For comparison, a 4-continent business class Oneworld Explorer ticket bought in N. America now goes for $8300. The same ticket bought in Italy is EUR5250, around $6600. The same ticket bought in Croatia (ferry to Split from Ancona) is $6000. But of course you have to get to Italy and/or Croatia in the first place. Can you do so for less than $1700 - $2300? (And there are other benefits to N. Americans buying in Europe relating to stopover allowances in N. America, etc.) And BTW, the miles harvest off a DONE4 can be profound and can have major benefits in non-RTW travel later.
Read the sticky threads (very important), get the Excel viewer to see the spreadsheet, look at the various rules
here, look at other RTW programs
here, and start planning!
Again, welcome to FT!