I did the IMC while studying for my ATPL exams / hour building, and found it very useful as a lead in to the IR. It also gave me something constructive to do with my hours rather than burning holes in the sky. It helped me with things like holding patterns, entries, timings, NDB and VOR tracking, reading the instruments correctly, unusual attitude recovery, how to read approach plates, to name a few. These were all things I didn't need to learn from scratch when I started the IR and meant I could concentrate more on other things, such as managing the extra speed/workload of a twin, single engine ops, airways and routes, increased RT, etc.
However, if you are finding it difficult to do all the study required then your ATPL exams are more important.