Preserve last updated records

Table. Buffer is used to cache results. For large tables, Table The Buffer function may slow down the calculation.
All data needs to be traversed whether it is de duplication or grouping. But, if the data source supports query folding (query folding may be interrupted by other operations), grouping is excellent, because grouping operations will be performed on the server instead of locally. However, if you use Table Buffer function to cache data is undoubtedly a very bad decision.
In conclusion, if the data source supports query folding, you should use grouping. I personally feel that there is no difference between other data sources.

It is all related to your data structure, if the number of records is not that much there is no difference, but if you are faced with too much data, and the number of groups that you want to extract the last record for them is less than around thousand go for Table.Group otherwise use Table.Buffer and Table.Sort technique