1. maintenance: Rig and Ren. Wax.
2 & 3. tough Question: all damascus is far from equal. Depends upon the skill of the forger, as well as the steel and technique used. Antique damascus and modern damascus (which is actually pattern welded steel of 2 or more types) are quite different. If the maker is going for performance rather than developing an attractive or unusual pattern and if they are skilled modern damascus can be made into high performing knife.
Real world example. Ray Kirk won a cutting contest with a damascus blade he forged a couple of years ago. The cutting contest was designed to generally test the edge durability in several varied tasks varying from hard impact (chopping wood) to more precise tasks.
Since I have never used an Antique damascus knife, I really can not make a legit comparison.