If you enable the DNSSEC, for most of the clients it's a no-op. As they are highly unlikely to verify the signatures, etc.
Yet, for these who do verify, enabling DNSSEC for the domain is somewhat a one-way road. I don't know the provider you mention, but in order to transfer such a domain to a different 3rd party DNS service, you would need both:
- support at the old vendor to extract the private keys,
- support at the new vendor to import external private keys.
Otherwise your DNSSec-enabled clients will see faults with domain name lookups in the transition period.