How many people?
If it is just one or two you will be fine. The cabin is a bit smaller and only has one TV and a "love seat" instead of a full sized couch.
I have sailed in both the mini-suite and in a regular balcony and overall I didn't have a problem with the size of the balcony cabin.
If you are sailing with more than two people then you will notice the difference and wish for the mini.