If your IFR skills are sharp, the RV will be no problem in IFR conditions. An autopilot is nice, as others have said, but if you know how to trim the aircraft then I wouldn't consider it a go/no-go item.
Whenever this question comes up, I feel that the discussion always turns towards the negative aspects of the RV in IMC. Yeah, it's not going to stay-exactly-where-you-put-it like an Archer or 182. On the other hand, the light touch that makes the RV so fun to fly also makes it very capable during an ILS. I've done many ILSes to Cat-I mins (200 & ½) in mine and it's wonderfully responsive. Climb performance is another thing; being able to climb out of an inadvertant icing encounter or being able to be well above the MEA are also strengths relative to many other piston singles.
I would say that it's a great IFR platform, but one that requires proficiency more than others. It's probably less tolerant of the six-approaches-every-six-months crowd, but in exchange rewards the six-approaches-per-month crowd with performance, handling, and capability that exceeds the norm.
KCOQ RNAV (GPS) 17 to near-min LPV ceilings (click picture to watch video) on windy and wet day :