while airlines are offered options for different engines for the aircrafts, i would like to know what is the general difference between them, for example, GE, RR offering a same class engine for say a 777, what would be each company's attributes or rather "style". I hear they say RR engines are usually noisier but have higher thrusts. Is that a fair statement? Howbout the rest? Do the engines of each company have their own generic appearance for eg. PWs have a shorter cowling or longer exhaust cones? At this point i'm still not very familiar about engines...