In my opinion it's worth every penny. I had a lot of fun putting it into an old PC keyboard and testing games that I haven't played for 10 to 15 years!
OK, it's frustrating when a personal favourite doesn't work, but the majority do and the core is constantly undergoing improvement.
I'm glad I bought it and I'll be first in line to buy any improved models that come out at a later date.
Remember, it's support for the existing designs that is driving people to make improvements for the future. If you can aford it then buy a board, support the principal of the Minimig and encourage further development. :-)