Did an IMC course at West London Aero Club last year, partly as a result of the preceding 12 months having been a low hours year for me. I have to say it was some of the most enjoyable flying i have ever done. A truly potent mix of frustration, fear, exhilaration and pure joy (particularly when you finally do a decent NDB hold and approach!). Also, 20 hours next to a good instructor is going to do your general flying skills no harm at all.
I also took the opportuinity to do the course on a more complex a/c than I normally fly, a C182 (normally I fly PA-28's) so killed two birds with one stone by also getting used to the mysterious third lever!
Upon passing the flight test I actually decided not to impliment that rating; my circumstances now mean I simply cannot fly enough IMC hours to maintain my own personal safety standard.
However, what cannot be taken away is the basic IMC training, which gives you a certain level of confidence flying VFR on an inversion plagued summers day or simply using nav aids second nature