Autopilots in IMC?? My thoughts are:
First of all, know the performance of your autopilot and check it out on the ground.
Second, if flying only occasionally in IMC, use the autopilot as an 'emergency' back up to hand flying. This keeps your IMC up to scratch and currency is vital. Have the heading bug pre-set on your chosen heading, so if you have any sort of problem, you only have to engage the a/p in bug mode. Then if you need to turn, move the bug 20 degrees at a time and monitor all the usual instruments for problems. You could also do this in an emergency to fly an SRA or QGH approach, if you were not current and (oh dear!) caught in IMC. However, it really is only a 'get out of jail card.'
Third, if you are current in IMC flying, do use the autopilot. It helps enormously when you have to review charts/plates etc or consider a diversion, or even just note ATC instructions. Its a vital tool for IFR regulars in my opinion and leaves some brain free for situational awareness.
Fourth, I have an STech 20 autopilot (no altitude capture/hold). I am not personally familiar with three-axis types, but there have been a couple of fatal accidents in recent years, where the autopilot is believed to a have flown the a/c very out of trim. On disconnect, the forces required to maintain controlled flight are extreme and would be unexpected, so very, very dangerous. I would therefore be interested how regular IFR pilots with (single) 3-axis autopilots monitor that all is well. And then there is ice.....
Regards