Welcome Nicolas,
You're English is just fine!
The only "problem" with IMM guns is that not as many powders will safely make Major in them. If you're shooting IPSC in Europe that would be less of a concern with the slightly lower power factor and the slightly heavier minimum bullet weight. Trying to make Major out of an IMM with 115gr bullets can be done, but I think they're only about two or three powders they normally recommend for it.
I know that doesn't answer your question very well, but it really is one of those things that people have to try for themselves before deciding. Good luck with the decision! R,
One of my blasters is an IMM, 10grains of 3N38 or 10.2 of SP-2 will make major with a 124 jhp every time. I have five other open guns and the IMM shoots flatter by a long shot!