I bought the #5 for $19 plus shipping.
It is a new plane. So it needs a bit more tuning than a plane that is used regularly and taken care of. So in my opinion those that put it down because it takes longer to tune than a well used and cared for Stanley are not comparing apples to apples. What better way to learn about hand planes than to buy a new one and have to clean, tune and use it. Yes, you can get a Stanley on e-bay for $30 that will work as well, and possibly be more enjoyable to use. I am no kind of expert, but I think the Groz is a good deal at that price, if you want a new useable plane. I enjoyed making it a smooth working tool.
The issues: The rear handle was not flush to the body and needed to be sanded. The blade took about 40 minutes to hand sharpen to a very nice edge. The throat is not very smooth; I am probably not going to do too much about that now. The body is pretty flat, but once again it is new, and needed a bit of conditioning. The depth adjustment lever is not very well built, but works.
Overall, I wouldn't plan on building a set or collection out of them. I would compare them to a B&D tool. It will get the job done if you are patient. But it would be so much nicer to have a ______ . If you can justify the price.