Direct die contact completely removes the IHS. In our interview with Der8auer, thermal improvement largely hinges on the specific CPU that was delidded. Some have shown temperature reductions upwards of 10C, and most show a reduction in the core-to-core temperature delta overall. Other CPUs exhibit less senational thermal swings -- it just depends on the unit, particularly on which SKU the CPU is.
This is a product not intended for average consumers. Risk is mitigated by using the die frame, but there is always inherent risk in the entire delid process. Using the right tools, most of this risk becomes that of user error -- but it's certainly possible that user error happens in first attempts. We'd suggest our "What We've Learned" video for some pointers, if considering this process. The price sits at around $60, which seems reasonable for the high level of precision that Der8auer specifies: 0.52-0.58mm tolerance from the thin part of the configuration, which is an expensive level of precision to manufacture -- speaking from experience. It's also a niche product with, likely, relatively low production quantities, and it's targeting $2000 CPUs -- so $60 seems reasonable.
As for cooling benefit, we'll find out soon and let you all know.
Editorial: Steve Burke
Video: Andrew Coleman & Keegan Gallick