It depends from individual to individual. Both options are good. Many investors prefer an NFO over existing funds as a new fund is available at the absolute price. The absolute price in most cases is generally INR 10. Investor might think that investing in NFO could earn them higher return.
Personally I prefer in investing in existing MF because of the following reason.
1.Existing fund has a proven track record whereas an NFO is a completely new fund with no past record.
2.NFO comes with high initial expense.
3.Trust9 in the existing fund manager because of his past records over the years whereas the same cannot be said for a NFO.
Hope this address your query.