The ease with which it was developed for our needs (crypto trading) - both technical aspects & branding / marketing side were very well handled by them! They also provided great support during initial development phase too :).
Only thing I dislike about my experience so far has been price point but other than that everything else seems ok :) We are solving two problems at once here i would say:- 1.) Ease/integration wtih existing banking infrastructure 2.). Branding issues faced while implementing new solutions within traditional financial services sector etc.