I buy from them quite a bit, and I generally buy other items along with the precuts. I like to purchase yardage of at least one fabric in the precut and then I know I've got sashing/border/binding fabric to go with the precuts. For charm packs, I often make bags from them, so I make sure to get enough fabric to make my handles.
I do have a drawer full of precuts and they really come in handy for quick projects or for gifts for my quilting buddies or giveaways on my blog.
I find the shop is wonderful to buy from; they ship quickly and I've only had very positive interactions with them.
When evaluating their deals, you do have to take into account that not all precuts have the same number of fabrics. They are working with manufacturers to standardize this to make it easy to compare the value you are getting.