Diesel electric is better. Diesel submarines have an advantage against surface ships as opposed to a nuclear submarine, ask anyone who is in the navy.
The reason that diesels are so much quieter than nuclear while on battery, is that they are only spinning a couple electric motors connected to the screws. No reduction gears , no main coolant pumps, other circulation equipment blowers or bullshit.
One other thing to keep in mind is the size difference between a ginormous nuclear submarine - except Alphas - from either side and a smallish diesel boat. There's a lot of difference in water displacement. The Ufa was around 2,000 tons submerged, and Los Angeles class depending on block is anywhere from 8 to 10,000 tons.
Ufa, one of Russia's Project 636.3 diesel-electric submarines, is touted as the most advanced stealth vessel in the world. The improved kilo-class submarines have been dubbed a "black hole" and are believed to be among the world's quietest submarines.
