In my opinion, you'd be hard put to find a better all mahogany concert in that price range than the Kiwaya KTC-1 or KTC-2.
I plan on getting a Kiwaya eventually sometime in the future. It's just one of those ukes that looks very appealing to me (and you can get the soprano and concert with 12 fret to the body).
I do love my LoPrinzi, and plan on ordering a all solid mahogany soprano from Donna as my next purchase.
If you do decide to go with a LoPrinzi concert, and you are willing to get one made. You can request the older larger body style if you think her current one is too small. I think it's a extra cost of $25.
Here is the difference between the newer (smaller) body style, and the older (larger) one.
What does "professional level" mean? .....
That is one of those musical industry things that is a great marketing term. They label instruments in various ways- student, beginner, step up, intermediate, pro, etc. There is nothing to stop a good player from using anything they want to make great music, but the idea is supposedly that one needs a "professional" instrument. If an instrument is well designed so it plays and intonates well it can certainly be played.