I know this is a bit long-winded, but let me take a crack at this:
If exposed to excessive radiation, the DNA in a human cell can become degraded to the point where it becomes cancerous. If you were to use the genetic information in this cell to produce a clone (take Dolly the sheep for instance), you would have corrupt genetic code. If you were to clone the genetic material from a healthy, non-cancerous cell, you would get a human that develops to be the same as the original. The fact that both healthy and diseased cells can live in the same organism and both be derived from the same base genetic code can be applied to plants as well.
If we apply the same idea to plant cells, consider an offshoot from the main stem of the plant that contains slightly different genetic information. If the alteration in genetic information degrades the quality of the branch, then a clone grown from a clipping off this branch would be of lesser quality. But the same situation could produce a slightly better clone as well. It may not be genetically identical (though it could be), but it will likely be so very similar to the original genetic code that there is no perceivable difference in terms of potency, quality, bud sizes, taste, etc. Obviously, if you were to expose the plant to excessive radiation as with the animal cell example, you could see genetic degradation to the point of having a diseased plant.
Under good conditions, you could clone a clone and the difference in genetic code would be minimal if any, and given such an insignificant difference, you would expect not to notice any difference. If you did notice a difference, you could decide whether the difference was good or bad and clone only those that had actually improved.
Does anyone take issue with this? Do I not understand my cellular biology well enough?