I'm doing it temporarily before bringing young family over. It's not really all that hard, you do need to think outside the box sometimes. With respect to them I think the older guys find it a lot tougher than the relatively younger ones. West coast/Honolulu, between jumpseating on company metal, other freighter airlines, UA/DL/AA or buying a discounted ticket on QF/JQ I've never been home a day later than planned nor bought a confirmed seat. Haven't had to consider coming home via Korea/Japan/Hong Kong from Anchorage but those are options also. I've had a harder time getting from Sydney to Melbourne after crossing the Pacific sometimes! It's allowed us to sort out affairs at home with no rush. Now I've seen it I'd be okay to do it again if we need to be back in Australia for a while.
Culture is overall positive. A lot of angst around the USA big boys getting massive pay increases that we aren't, increasing attrition as a result. That's not an option for us so I don't let it bother me. Everyone is super chill. 747 is a dream if a little noisy.
Training was not difficult but it was lengthy. I had a few delays involving going home, but the norm is now around 3.5 months in a row in Miami including your ATP course. A lot of the guys falling over during progress checks or actual checks typically didn't have any or much jet/multi crew time - struggled with using the CDU, flight directors, understanding FMAs etc.
I'm a little over a year here and really happy with my choice, couldn't fathom going back to 4 sector days up and down the east coast, but we all like different things. Feel free to private message.