one thing that makes the DOA games appealing for me, particularly as a party game is that its very easy to pick up but difficult to master.
the controls are pretty simple and straight forward and just playing around anyone can figure out some basic combos/moves and put up a decent fight with little knowledge of the game.
Much like the 2D MK games, against low-mid level players you can get by using just the basic game mechanics that are static across all the characters.
There are a lot of intricacies there for the people who like that sort of stuff.. knowing when to use certain moves against other moves etc. A master DOA player will school EVERYONE.
DOA4 is a little more geared towards the mid-high level players then previous versions were but it's still a really fun game and still easy for new people to pick up.
4player Tag Battles are the best.. I've been playing 4 way DOA since DOA2 on the Dreamcast... it's what keeps me coming back to the game

Tekken is a great series but I never really got into it because it relies too heavily on memorization of long combos and movies... and is just too complex for the amount of time I'd want to dedicate to a game like that... I find it's hard for people to pick up and play without any prior experience too...
I'm also a huge fan of Killer Instinct and Mortal Kombat games pre MK4