All the geometry angles and measurements in the world won't tell you how a bike will fit you(unless they are identicle to the bike you are currently riding), at best they will get you in the ballpark, enough so that you know which dealer to visit to "test ride" your new bike. Since suspension bikes necessitated interrupted seat tubes that no longer originate from the BB, Seat tube angles mean very little and Effective top tube measurements even less (unless you ride with your seat at headtube height all the time) This new "standard" will work well for DH and FR bikes where you stand 90% of the time, for AM and Trail bikes however, it becomes important to know where the Seat tube angle will position your seat when you are sat down pedalling. Hard to tell from a brochure, hence the need for test riding! I like Dave Turners idea of leaving off Eff top tube length on DH bikes (its irrelevant and confusing to customers!)