Copied from the other, similar thread.
Most of our customers who have been through the system generally reckon that doing an IMC rating whilst hour building makes sense. Certainly more sense than just boring holes in the sky for little benefit.
An IMC rating gives you more flexibility when flying solo building your hours, it gives IF skills that can built upon doing the IR training and it is cheaper to keep current than an IR if you subsequently take a while to get a job!
There IS little point in doing it as an add on after completing hours building, though - you can get an IMC rating signed off by the CAA examiner when you do your IRT - but as a near-freebie to be done during hour building it makes plenty of sense.