Seed mixes are always a good topic for discussion at Bountiful Gardens; we are always trying to think of ways to make more seeds more available to our gardeners and mixes are always popular. They can be a boon for someone with limited space who craves inexpensive variety.
Our mixes are not for the person who wants a specific variety for a specific purpose, they are for trying out a wide variety of types all at once. If one works particularly well for you, you could try saving seed from this plant - even though it will have crossed a little, it might still work for you (might even be better). This is a good cheap way to start saving seed as well. We most likely cannot easily identify a specific variety from our mixes that has grown in your garden.
Mixes allow you to experiment with interesting new varieties, and allow the seed-saver to select locally-adapted types. Mixes may vary from year to year, depending on what's available, and may not be the varieties listed seperately in our catalog. Remember that these are truly mixes, not a collection of separate packets.