The main difference in Vietnamese vs. Chinese egg rolls is the use of meat/shrimp. I LOVE Vietnamese egg rolls, any time I refer to egg rolls, these are the type I mean. They are so good, I'm excited just thinking about making them! My Dad is going to get the ingredients today and I will prep the filling tonight, roll them Friday night and fry them Saturday.

Just so I don't get too tired making a big batch.
I first started making egg rolls when I moved out on my own. My first batch was TERRIBLE! :? The meat was tough and I didn't use the correct ingredients. I've continuously played around with how to improve them. Here are some things to watch out for: how you roll them. If the egg rolls are not tight enough, the air pockets will make them go soggy FAST. This is what happened to the first batch. I rolled too fast, and didn't take enough care to make sure they were tight w/ no air pockets. Also watch the meat to shrimp ratio. Should be about 2 parts ground pork 1 part ground shrimp (roughly). As for cooking, I never precook my meat before filling. I avoid this only because numerous family friends have told me not to, that the texture of the meat will change, etc. (side note: one woman I recently talked to said she fills, rolls, wraps, then microwaves for a few minutes, then deep fries, just to brown. She's considered a very good cook, so I may try this one day, since I'm watching my weight...)
HotnSpicy, not sure how you are handling the egg rolls after they are cooked, but make sure to follow 2 golden rules of egg roll cooking: 1. never let it rest laying down, always stand it up vertically in a colander 2. never line the colander with paper towels, or anything. This is yet again one of the things I screwed up in the first batch.
As with all home cooking, each family is different, some swear by using taro, others do not. Some love wood ear (like me), others do not. I'll let you all know how it goes later!