The national validations of an EP patent offer you the opportunity to allow the patent to lapse in certain countries while remaining in force in other countries. The unitary patent is an “all or nothing” patent for which you will have to pay a renewal fee (equivalent to the rate for four countries) for every year in which you want the patent to remain in force.
If validation in one or two states provides sufficient coverage, the unitary patent is likely to be more expensive in terms of renewal fees and validation costs; validating an EP patent nationally in certain countries, such as the UK, France and Germany, does not require any translations beyond the claims translations needed for grant (which are also needed for a unitary patent). The unitary patent requires one full translation into a second European language.
You may wish to avoid the jurisdiction of the UPC, for example to avoid central revocation by the UPC. This can only be done by securing national validations of an EP patent and opting out of the jurisdiction of the UPC. It is not possible for a Unitary Patent to be opted out of the jurisdiction of the UPC.
Having different patents in different European countries may offer some advantages when it comes to licensing to different companies in different states. If a Unitary Patent is licenced to different parties in different states, it would be prudent to include in any license agreement a clause relating to which parties can risk a counterclaim for revocation (which would be effective for all states) in a UPC infringement action. Agreement on such a clause may be difficult to reach.
For more information please contact Martin Jackson