GoneWest - nice rhetoric, but wrong.
I did the IMC rating, and used it in anger and frequently (deliberately). That IN NO WAY prepared me for what I was expected to do in terms of accuracy of flying for the FAA IR.
The "US geography and charts etc differences" are minor compared with the "quality of flying" requirements. Maybe NAC and the FAA examiner I had weren't typical - I dunno - but they certainly expected far better than the IMC rating examiner and renewal CFIs here.
Yes, I do plan to keep the FAA IR current. Most trips of any distance with another of our group, I take my hood and do the necessary tracking, holds, approaches, etc.
The plan - soon- is to put the group aircraft onto the N-reg, which will mean we can fly IFR outside the UK.