The UK will begin issuing (non-expiring) EASA licences on 17 September. Any licence issued before that date, although being deemed to be an EASA licence, will be issued in accordance with JAA requirements for a period of 5 years, after which it will be replaced with a non-expiring EASA licence. The currently published fee for the replacement of a JAR PPL with an EASA PPL is £73, which can be expected to increase at least by inflation over the 5 year life of the JAR licence.
The decision is simple - is a 4-6 week delay in receiving your licence worth £73 to you?