Essentially Gasoline burns much better than Diesel, which means its much easier to ignite Gasoline. A diesal engine has to use a compression ignition to burn the fuel, while gasoline doesn't need to do this and simply uses the spark plug to create combustion. Gasoline engines tend to make more horsepower, sound better, and perform better. Diesel engines make less horsepower but can create incredible amounts of torque, they tend to be noisey but a lot less than they used too; they used to smell very bad too but with new clean diesel technology that has indeed all changed. Also Diesel engines tend to be more fuel efficient and can last forever. Basically same concept in terms of internal combustion but due to Diesel's low combustion properties a combustion ignition needs to take place during the final stage of ignition.
actually Diesel burns quite fine... diesels are great naturally aspirated because of their extremely high compression ratios. and diesel engines make plenty of power, diesels dont use spark plugs cause they're not needed... compression alone is enough, cant do that with gasoline. and turbo diesels.... they're awesome.... lots of boost potential..... my favorite diesel is VW's TDI, twin-charged (turbo and super-charged) 1.4L engine.... gets 50mpg and still makes great power. the reason diesel isn't as popular is because until recently they smelled bad (low-sulfur diesel wasn't available) and were noisy.... a big diesel is still loud, but most diesel cars are indistinguishable from gasoline cars... and biodiesel is great as well, you can make it yourself out of used vegetable oil if you want.... in fact, when Rudolf Diesel originally debuted his engine he ran it on peanut oil.
Actually gasoline has an octane rating from about 87-96 while diesels octane rating is more like 40. Therefore it is more difficult to burn, hence the compression needed rather than using the stanard otto cycle. Sure diesel has its benefits over Gasoline motors but power wise Gasoline agian due to its superior burning quality makes more power. Diesel burning slow produces greater gas mileage and a turbo diesel can make incredible torque.