First off let us establish that Tudor is a subsidiary of Rolex. The Tudor name has always been used for Rolex's second grade of watches. In recent times they have employed an oyster type case which says "Oyster Case by Rolex Geneva", or something to that effect. In the old days they had non waterproof cases as well as the waterproof type, just as Rolex did. The movements were contract movements, as they are today, being manufactured by other makers such as Font and ETA. I am only repeating what I have picked up from my watchmaker. The information is accurate but likely incomplete as we are dealing with a very long history. The parts on the cases with the exception of some of the crowns and crystals will not in anyway interchange. The sizes were purposely made slightly different so that people wouldn't try and turn a Tudor into a Rolex. As to the grade of the stainless steel two people have stated that it is of a different grade so I will assume that to be the case. You can however, even find Tudor Oyster Cased watches from the 40's in solid 14k so I don't know why they would use a lesser grade of steel today, its not that expensive. They also did use bumper automatic movements in the forties. A friend had a beautiful large bubbleback Tudor bumper automaitc in solid 14k Pink gold. On another note I will tell you that I had a Tudor Auto Prince Oysterdate, from the early seventies, serviced recently for a friend of mine and it kept literally spot on time...much better than any Rolex I have ever owned. I almost didn't let him have it back! Some watches are just better than others. This one behaved like that on the first try. Generally that is a testament to the quality of the person doing the work I would say, and also how many people have messed it up before hand. If you bought a new Rolex and had it serviced properly by them or other qualified people within the recommended service periods they would continue to keep great time. People complain so much about Rolex this and that. My favorite are the complaints about the 1030 mvt. which according to my watchmaker is an Excellent movement! It is not a 1570 but neither is a Y Block Ford Motor from the 50's a 289/302. It was such a vast improvement over the NA and A 260 movements that preceded it that the criticisms boggle the mind. Just as the Y block was revolutionary compared to the old flathead Ford the 1030 had features that put it in a class above the earlier movements. The problems that occur with a 1030 are generally because no one ever cleaned and oiled it. Dirty parts with no oil...wear out and give trouble. So will your washing machine. My non chronometer grade 50's sub with a 1030 is now within 3 seconds a day...With patience and perseverence, most any of these watches, Rolex or Tudor can be made to keep excellent time. The information Nick has given may be representative of the current specifications. Heck most quartz watches won't stay accurate within 2 seconds a day even though they all say they do. I never had one that did.

Best regards.