I'm a techie so this may bias me, but I definitely prefer to see What and How before Why. The reason is, you as the solution provider are not in the position to tell me what problems you'll actually solve for me. You can make high-level promises, but whether your solution can realize them in context of my business and my tooling, depends on how they relate to your What and How. So either you tell me your What and How, or I have to tell you everything about my business and my problems - and since I'm on your landing page and we aren't really talking, I care and expect to see primarily your What and How.