While it's interesting to see the relationship map, I wouldn't put too much stock into the information one way or the other. I happen to work for a company majority-owned by KKR, but we don't share much with their other investments, especially from an operational/quality standpoint. So while SBD may own Craftsman tools, it's unlikely that it has much affect on the products/quality of MAC Tools. The two companies likely share no common employees or even attend the same meetings.
I generally buy my tools based off of what I already have, and what I perceive the company excels in. If I need a solid power tool, DeWalt or Ridgid are generally my go-to as I've had good luck with several of their products. However, I don't go out of my way to buy DeWalt hand tools/drill bits. I use Craftsman and Kobalt mechanics tools because they have held up well to my shadetree mechanic/weekend project abuse, where cheaper Stanley models have sometimes been problematic. I will switch brands for different tool segments, so I don't think any one brand (or parent company) holds an advantage that all of their products are equal in quality/value.