The Tritonians are all very strong and pretty much all of them are trained as warriors from a young age. One of the other cities of Atlantis (can't remember the name) has an extremely large armoury of advanced weaponry technology and are all extremely strong aswell (one managed to fight Aquaman pretty evenly). Another city is filled with female magic users. A group them managed to cause a Millenium Giant pain.
The DC Atlantis encompasses alot. Aquaman agthered together the main cities of Atlantis once to repel an alien invasion. And repel they did.
I guess that DC Atlanteans have more magic, but Marvel ones aren't something to underestimate either. Doctor Strange didn't know anything about theirs, and was quite impressed that he still had something that powerful to learn (that is why he went there for assistance). Naga, another Atlantean/Lemurian (if Lemurians are included, they are technically Atlanteans) magic user with Serpent Crown (Lemurian magical object) was able to match Strange in battle for hours. A pathetic magical user with Sword of Kamuu and Eye of Zartra: http://www.marvunapp.com/Appendix3/swordofkamuu.htm
Was able to easily defeat Doctor Strange in magical battle. Then there is the Trident of Neptune, which I think that can only be used by Namor, since only the rightful successor to the throne of Neptune can use it. And I don't think Aquaman and Namor are included here?
I'd say that Marvel Atlantis is more warrior like, though. They are pretty much trained from birth to be warriors, honorable and noble. Each of them is roughly something like Class 5-10, and they have great speed too. In only few days they made a fleet from scratch that was able to invade New York in minutes. Even Reed Richards was impressed of their technology. Plus, if they get some of the beings that have lived there (Like Tamara Rahn and Tiger Shark) their army becomes even better.