Wow, you sound like me as far as trying a ton of therapists. Sorry I don't think I can answer your question very reliably. I'd lean toward the one you think is challenging though, because if I were you and I didn't, I know I'd keep wondering about the challenging one if I didn't talk to them. Actually, I guess I did that myself-- about a year ago I was trying to decide about going back to a challenging t who I had seen briefly before, or continuing with a nicer one. I got up my courage eventually and I went to the challenging one. I continued for about a year. I stopped a few months ago and I'm struggling to make a decision whether to switch back to a nicer one now. I think I might be able to get more out of talking with a nicer one now, idk. I'm glad I went to the challenging one anyway because I'd still be wondering if I hadn't. I may go back to him but I'm not sure. As far as getting hurt by the challenging one, he has said some things that probably hurt me some (I mean more than just at the moment he said them), but overall I think it was better that I did it anyway. I think that since therapists generally try not to hurt people, even the pushy ones limit their pushiness.

Good luck!

Edit: I just reread your post. I had missed that the pushy therapist was a cognitive behavioral therapist before. I don't like cognitive behavioral therapy much, so I might not go to that one, idk. I think other posters gave a good explanation about the differences between cognitive behavioral versus more analytical therapy (as best as I know). OTOH, I think personal style counts for a lot, maybe more than the type of therapy. You said you don't think your current t can help, and that seems like it could be a red flag reason to switch. You've given it a good try with her- 5 sessions- so now would be a good time to decide I think.