Hi nickb777
in general when deciding to replace a standard Lithium widget with a custom component you need to ensure that you can recreate all the features of the standard widget that you need. If this is not possible - then you can consider a simple re-skinning of the standard component.
That said - you are right in taking performance into consideration and trying to minimize the number of rest calls that you will need, especially for components that will live in a busy page (such as the community homepage). Of course it is all related to the metrics of your community and what are your goals etc ...
Hopes this gives some ideas!
