None, they all have their flaws. DELF is trying to get you by testing your logic as well as your level of French. I find it unecessary tough, like your worst exam back in your shcool days. It doesn't just test the useful stuff and if you don't pay attention to the extreme you will fall into one of the traps. TEFAQ asked you in the first part to be able to ask 10 questions about something (an activity you may want to take part to for example) and in the second part to convince someone of doing something you probably never heard of (like spending a night in a hotel made of ice) or something good for them (like changing job, doing something more healthy). Undecisive people and pushovers are clearly disadvantaged here. TCFQ ask you to answer 6 random questions at lenght. They could be vague and complex (and difficult to answer even in your mother tongue) like "talk to me about the multiculturalism of your town" . People who usually answer questions with short answers and people who don't read the papers are disadvantaged here.

merci :-)

well said caroline! a_a very good advice