Climb, no clue on Global Pilot Serv... I have never heard of them.
HNA and it's subs pay more that the top 3 CN airlines... I would compare contracts but also look into pairings, QOL, bonuses, etc... Some of my friends at other airlines here in CN get pay similar, but they do 4 on 2 off, as we do an avg of 13-14 duty days per month, as our trips are EXTREMELY effective... Also as the bases are different, the cost of living could make a huge difference. So many factors to take into consideration.
Gather all the info you can before making the decision...