Well the one thing to say really is that you must insist on your lessons to be 45 minutes. If i convert what you are paying into euros it seems to be working out about the same as what I was paying for 50 minute lessons. I attended one of the more expensive studios in town.
I learned a lot and, comparing what I learned from my instructors and what I learned reading the discussions here, to what I saw other less expensive studios do I can't say I regret it.

Of course a studio is only as good as it's instructors and those will be just as good if they teach at a cheaper studio.
If you are serious about dancing you will want to choose the instructor, not the studio (as long as money is not that great an issue).
For example two of the male isntructors I had (one only in groups though he suggested we should do some private lessons together to help me with my latin - the other I did training sessions with to work on my smooth technique and frame) both have left my old studio. The first to open his own studio, the other to work at a studio which, as far as I had heard did not really have the best reputation.
Would I now go to my old studio and pay the same price? Of course not, the male instructors I need aren't there. Instead, half the new ones are guys I used to train with, who only now became instructors to fill our old instructors' shoes.
I cant take lessons from someone who just a yer ago I was teasing with remarks like "What is that supposed to be? I mean I recognise the figure to be what I did yesterday during my tango practice, but you seem to be doing a foxtrot."
Would I now go to the other studio that is cheaper but that I hadn't heard good things about? Of course, they now got two instructors I'd love to work with.

If a studio is expensive or cheap sadly doesnt affect what you will learn. The instructors as simple employees only get their salary and that doesnt really differ that much from studio to studio.


Oh and listen to Ellen, you do not want to fancy your instructor. I couldnt stop myself and went through such a bad fight with mine last year... the poor regulars here had to put up with me ;)
And we are still picking up the pieces. It took us nearly a year to be able to say "hello" to each other again:) (thogh we are making progress: just a week ago we managed to actually smile when seeing one another)