Pork is probably the most common version of sweet-and-sour that you see in Chinese restaurants–there’s even a vegan version of it you can buy in most stores. In case you’re looking for something more refined (but maybe not as easy or meatless), here’s Serious Eats’ take on it.
The terms are used interchangeably here, and seemingly in most other places as well. The biggest takeaway from the spring vs. egg roll debate is that spring rolls are originally from China, but have been Americanized along the way (while egg rolls were always American).
They tend to have a thinner wrapper than egg rolls, and are often also associated with the transparent rice paper rolls you tend to see in Vietnamese and Thai restaurants.