Savage Worlds is definitely light, fast, and easy to use. And it can accommodate any genre with relative ease. However if you try and run a party through an old school dungeon crawl you're likely to slaughter the party very quickly.
The thing you have to remember is that D&D, especially older editions, is a game of attrition. It's designed to gradually wear down your resources and run you through challenge after challenge until you earn enough experience to level. Savage Worlds on the other hand is a game of action, where every challenge has the potential to be lethal. When converting D&D material to SW the first thing most people will tell you is weed out all the combats that aren't important to the story. You can totally run an adventure with the feel of an old school dungeon crawl. You just have to go about it a little differently because of the difference in the systems.