PlankBender,
I did my MECIR full time, and I know many others who also have. We're all still living, after quite a few renewals, and working in roles which we fly IFR every day.
Very few of us went straight into an IFR job after doing our MECIR.
I'd encourage anyone to do their MECIR in one hit. The learning process is made a bit easier by the constant learning.
However, I'd also encourage anyone with a fresh rating, to step into the IFR world (once you have it), very slowly. Don't make the first time you go IFR, a day where you're dodging weather and everything is down at the minima's.
morno