Integirty 10.8 added the ability to compare two document version, but the same feature does not exist for comparing two individual node versions or items which are not part of the document model. It would be really useful to see a marked-up difference of item item between two dates within the client.
The difference also needs to support different field types. If can be very difficult to know what has been added or removed when there is a list of relationship IDs. Parameter values are also very difficult to compare because of the way the values are stored.