Thank you for all the replies. I enjoy reading them. It was an interesting investigation for me to read through many books and data to try to arrive at my own conclusion of the Bismarck's place in the WW2 battleship pecking order. I had grown up being introduced to the Bismarck by the old 1960s movie, and when I got into college for engineering, because curious as to the real story behind the movie. Axis & Neutral Battleships (ANB) was my first foray into accounts with empirical data about Bismarck, rather the inanimate "character" of the movie. I was a bit surprised at what seemed to be a relatively unflattering assessment of Bismarck's capabilities. As such I continued some leisurly research over the years with Robert Ballard's book and Schlactshiff Bismarck by Bodo Herzog, and eventually did arrive back closer to the original assessment of Bismarck's superiority to other contemporary battleships.
ANB, I think, was correct to point out some flaws such as inadequate anti-aircraft capability, but some other criticisms seemed to be one-sided to the detriments of certain attributes of Bismarck's design without showing the counter-balancing benefits of those attributes. You all mentioned above the Bismarck's increased rate of fire, which was in part a result of the 4 twin turrent design that ANB criticised as wasting of armor weight. When factored into the traditional "throw weight" equation, if you will, the increased rate of fire takes Bismarck from the position of a very average looking offensive ship that can't really outslug WW1 British designs to a ship with a significant advantage over any other active ship in the world in May 1941. Add to that the increased muzzle velocity of its main battery, and the offensive gap between Bismarck and every other ship continues to widen. Again, this is May 1941, so comparisions are not being made to the South Dakotas, Iowas, and Yamato.
There are folks on this board that know alot more about ship design than me. Especially with all the detailed comments regarding Bismarck's armor design. All I can say to the criticism of ANB, that Bismarck wasted alot of armor weight from the quad turret design and the secondary battery that could have been better deployed to protect the ship, is this: whatever the Bismarck designers did, it sure worked well. It took the British something like 400 shells, many of them 14" and 16" at point blank range, plus at least 2 aircraft torpedos and 3 (3 was it?) more from Dorsetshire to sink Bismarck, and Ballard's research seems to suggest the sinking still required some scuttling charges from the German crew or possibly even more torpedos would've been needed. If the ship had not been rendered unmanuverable by Ark Royal, I am not sure it is clear the numerically superior British force would've sunk it, even if they had somehow been able to intercept it. Bismarck may likely have just weathered the storm of shells into waters guarded by the Luftwaffe until the British were forced to break off action due to air attacks or fuel shortage. I do not believe any other ship in WW2, or for that matter in history, even required that much punishment to sink, and that includes both Yamatos. The Yamatos were both sunk later in the war by standard ordinance from US Carrier base aircraft, albeit by significant numbers of such ordinace, but nothing close to the number of shells from KGV & Rodney, and certainly nothing like the specially designed 12,000 lb Tall Boy bombs used to destroy the Tirpitz.
Comparing Bismarck to other contemporary ships of 1941 sure does seem to warrent the tag of "most powerful battleship afloat" as the inaccurately Hollywood depicted Admiral from the 1960s movie would boast of. Comparing the ship to later war Yamatos, Iowas, etc, seems less of a certainty, but the real war battle suggests the ship might measure up alot better than the initial impression of 15" vs 18" guns, if you will. Bismarck demonstrated in the Battle of the Denmark Strait, probably the overwhelming most important attribute that any battleship can possess, specifically, the ability to put its main battery shells on target early and often in an engagement. While US ships showed the same, or perhaps even better ability, with their fire control radar in engagements in the Pacific, the Yamato struggled to find the mark in the battle against Taffy 3. It did score a few hits, but other than one small escort carrier, it under-performed against an opposition force it should have utterly crushed. Thankfully it failed. Contrast that with the battle of the Denmark Strait where Bismarck is legitimately outnumbered, specific tactics albeit, Holland rushed in without a broadside due to lack of armor, but Lutjens held his fire for 5 minutes. Also comparing the sinkings of the two ships, and the perception gleaned from their absorption of punishment, I might favor Bismarck over Yamato inspite of what the "tale of the tape" may say. The Iowas may be a different story as their ability to hit, especially in low visibility situations, would be at least as good as Bismarck, if not better due to fire control radar, but it does serve to mention that there is no data on their ability to absorb punishment as a couple of folks mentioned here, and also, their primary advantage, fire control radar, is something that made the old Pearl Harbor battleships quite formidable when it was retro-fitted on them in 1943-44. Bismarck was a 1941 design, before a number of these innovations of WW2 came to light, and relatively early in the war, Germany knew the path to victory was not in developing more advanced naval systems for their surface fleet. The Tirpitz added AA guns, but no other improvements were made as she had limited strategic importance, basically just be a threat to artic convoys. An Iowa without radar against a Bismarck, or a Bismarck with radar, might be a more apt comparison to ponder if the goal is to evaluate the best design of the era.