Any problems you here about I refer to as being a part of the Mac Rumors Effect.
Basically the MR boards attract a very large number of complainers versus the unheard Mac owners (the majority) that have never had a problem with their iMac. No need to worry about switching, it'll be painless.
This is true. You will find a few complains from me, but they are generally minimal or questioning in nature. On occasion, it's been frustration. However, don't let that scare you. I've had 7 Macs since 1988, including:
Mac SE
Performa 6115CD
iMac G3
iBook G3
PowerBook G4
PowerMac G5
MacBook Pro C2D
(I presently own the last 3 shown).
This dates back to 1988. Overall, my experience with these machines has been top-notch. I've had maybe a handful of issues in the last 19-20 years. I can't say the same about my friends and their Windows machines just in the last couple years.