It's not easy, bein' lean
If you’re tired of hearing about Lean Startups I recommend giving Fred’s post a quick read. It addresses most of the criticisms you may have heard.
My only negative observation is that “being lean” is an old idea that Eric Ries has done a great job of explaining anew.
When I led search on the Yahoo home page we were completely data driven. I worked with a team of great designers and engineers, and we came up with many cool (and many lame) ideas for how to improve the visibility and usefulness of search. We A/B tested everything. That said, we weren’t testing towards a specific vision. Our job was to increase search traffic, but the company did not have a coherent product vision to back this up. So we ended up learning a lot about specific things (search box colour, placement, functionality) but those learnings never connected to each other. It was like designing the next BMW coupe by optimizing the door handles and mirrors without paying attention to the cars overall performance.
Lean is about moving towards a vision through learning, and adjusting your vision based on what you learn. Effective execution is no substitute for strategy, and Eric recognizes that. Now go read the book