I endorse pretty well everything IO540 says here; the IMC Rating is an excellent tool if used properly.
It is hugely more affordable than the current JAA IR/SPA and the only real differences are that it cannot be used for IFR in Class A airspace - so that's no airways and SVFR only in Class A CTRs.
It is widely anticipated that the IMC Rating will be allowable as the first part of the draft JAA IR/SPA revision. It will also be the objective of a UK aviation group with an international representation to demonstrate the considerable merits of the IMC Rating to the wider world of EASAland; furthermore, should the UK NPPL become the future model for the EASA RPPL, it may well be possible to propose conditions (mainly medical, experience, training and testing) under which an IMC Rating and a night qualification could perhaps be added to the RPPL in the not-so-distant future.......