(1) What is your home airport? BKK/JFK/BOS
(2) What types of fares do you usually buy ? Y/B/M
(3) How many miles do you usually fly each year? ~50K I usually fly between BKK-JFK but I'll have multiple trips from either JFK or BKK to Europe starting this year.
(4) Do you have any kind of status at present? ROP Silver, I'm getting gold status next month
(5) What is most important to you in a FFP? Good award redemption rate
(6) Which routes do you fly most often (US Domestic, Transpacific etc) Transpacific
(7) Preferred Airlines TG > BR = ANA = OZ
(8) Do you travel for work or pleasure? (Can you chooose your airlines, class of service?) Pleasure, I can select my own airlines and class fare. Usually aim for the fare with 100% mileage accumulation.

I have been with TG ROP for over four years but didn't start to travel extensively until the last two years. I'm contemplating if I should switch to UA MileagePlus? I have just moved to the States, so it'll be easier to earn miles with American credit cards?

My first choice of carrier in transpacific flight is BR, followed by OZ since TG doesn't offer one. I would pick TG once they start operating to the US again. I fly TG exclusively on international flight to Europe (BKK-EUROPE). No strong preference in JFK/BOS to Europe. I usually pick Lufthansa or Austrian though. Flying from BKK to anywhere within Asia is almost exclusively TG unless OZ/NH/BR/SQ have great fares. I always pick flight that either is direct or has least connecting flights.

I recently used 70k to upgrade to business class on BR TPE-JFK while some people with different FF program use half of that amount. That's got me seriously consider switching to different FF program. If I make a switch, I'll redeem the 30k I have left on BKK-TPE, then start accumulate the miles with new program.