Yes, I think they are the best. They have strong expertise (for example they were commissioned to conduct studies by Ministry of Defense of Ukraine) and excellent accountability (some is public [0]).

In my eyes one of their highpoints which demonstrates their trustworthiness is the ~20 million dollars payment they received this year by undisclosed European (I think it was European) entity (government or private donors maybe)

[0] https://savelife.in.ua/en/reporting-en