1 on 1 or group lessons

I've never had over 3 in a class. Just look at smaller school and try to attend during their slow season. Anything over 4 should be a crime

Yep, until you're at an intermediate level I think small classes of 2-4 is the best way to go. After that (when everyone's reasonably able to converse without major errors) I think around 8 students would be best.

One on one is the best. I did years in the US of classroom (all sizes from 4-20) and after just one month of one-on-one in Guatemala it really paid off. Usually the interaction of others in the classroom really isn't worth your while.

One on one might be best for some intensive training - special problems you´re having - but a small group is, overall, a better enviornment for most people to learn in, IMO - and, therefore, that´s what I suggest you seriously consider.

Both have their advantages and disadvantages. When you do group lessons you learn from other people mistakes and from the questions they have and you didnt think about. Also it is nice to meet some people where you can go out with and do some stuff out side the school. Disadvantage is that when you are getting more advanced you will have some specific topics where you have problems with. This is a good time to switch to private lessons. There are also schools where you can combine private with group lessons. At our school oyou can do 2 hours of group lessons and than 2 hours private. In this case you have the advantage of both. As somebody else already said. Try to find a small school. If you go to a place where there are many schools visit them and see if you can get a test class to see how the classes are like. Also look how many minutes a lesson is. Often they say 20 lesson hours but a lesson hours is 50 or even 45 minutes. For prices be aware of extra hidden costs like cancelation costs, inscription fees, placement fees, material cost, administration fees etc. This can be a high percentage of your actual course fee.

Wouter