Charm packs are good if you are buying online. When you get the charm pack, you can view each fabric and make more informed decisions after visually inspecting and handling each fabric. Plus, you can test your stash to see if anything you already have in your personal stock will work with it. If you decide not to buy any of the fabrics, you can still use the charm pack, but you're not out of pocket for a lot of money.
I'm not a 'favorite designer' fabric buyer. Generally, if I like a fabric enough to buy it, that's what's important, not who designed it. I purchased a stash from the 1990's about a year ago and am continually amazed at how many of the fabrics work well with todays' fabrics. Alas, just as many don't! Or at least haven't yet!