List<KeyValuePair>
Dictionary<T Key, T Value>
1. Lighter
2. Insertion is faster in List
3. Searching is slower than Dictionary
4. This can be serialized to XMLSerializer
5. Changing the key,value is not possible. Keyvaluepair can be assigned value only during creation. If you want to change then remove and add new item in same place.
1. Heavy
2. Insertion is slower. Has to compute Hash
3. Searching is faster because of Hash.
4. Can't be serialized. Custom code is required.
5. You can change and update dictionary.