I'd be careful about asking questions like that. Nearly every club instructor is a volunteer, and many expect a lot of appreciation from students because of that. I wouldn't mind a guy asking questions like that, but I know instructors at my club who would get pretty offended if a student gave the impression that he's interviewing the instructor to decide if he's adequate. The truth is that some instructors have no idea how to teach. But it's better to just get what you can from them and then work with the better ones when you get the chance. I had a terrible instructor, but he was available so I worked with him and never complained. I gave him a small gift when I was done in appreciation of his time too. I soloed eventually and went on to keep improving on my own and with the advice of much better pilots in the club. So the point here is to remember that these guys are all volunteering their time for students, and nearly all of them are amateurs at both flying and teaching. Do work with multiple people if you can, but don't get aggravated if the experience is less than stellar.