WOW. In a nutshell:
Choices are editable in a table, modifiers are not.
Choices - add variations to the product, the product's name and SKU. ie: Color: red, blue, green. Size: S, M, L. Editing the possible combinations is possible via the edit product page > Edit Product Variations. So... you can make the SKU for a Red, Large: 001RL. The Blue, Small model can have a SKU: 001BS. Also, the NAME of the item can change to anything you'd wish and will change as selections are made... "Shirt Red Large". PLUS the image can change as choices are clicked to see what red or blue versions of the product look like in real time on the product page.
Modifiers - are used to change the price. The name and SKU don't change, so inventory for Shirt Red Large isn't possible.
Shared choices are used to assign a set of choices OR modifiers to any number of products. If you edit a shared choice, the choice or modifier list changes for ALL products using it. Modifiers and choices can be shared.
If (like me) you miss the ability to create a set of choices, assign them to a product then edit them on the product's edit page (as with SF6), do what I do. I make a dummy product, build a set of choices or modifiers on that product's edit page and save it. If I need that set of choices altered a bit, I clone the dummy product and then edit just that new product's choices. Saves building nearly identical choices.
If you use a LOT of choices on a product (I've got some with 8, each with up to 8 selections), use modifiers and forget editing SKUs and images. The number of possible combinations can get into the hundreds and editing different SKUs for each isn't worth the time unless you can live with the automatically assigned appendages.
Have a look at my cabinets at:
http://www.missionfurnis...ne-Cabinet__MAS742S.aspxI use only modifiers because they almost all need to alter the price on most of my products.
It took me a month to learn all this. I hope I got it right enough to get you going.
I strongly suggest you watch the videos at:
http://www.bvsoftware.com/bvcommerce5manual/http://www.bvsoftware.com/bvc2004/manual/