well first you got to realice that brands of the seeds are like brands of cloths, or something like the milk in the super market. you can get cheap milk or seeds, and it will work but will not have all the good stuff the expensiver might have. Also not always the expensiver is the best...

Sensi is a GREAT brand anything you buy from them is good, they have an incredible reputation all over the world.

So going back to your question whats the difference between the strain in between the brands? well it might be a totally different plant from brand to brand, or might be similar from brand to brand.

But you are the one who will discover the difference, so tell us how it went!!!