I just made the move three weeks ago.
Mostly depends on what you want from it.
The iMac is not upgradable (except for the RAM), a PC is upgradable.
I dont buy into the iMac is more expensive theory, if you compare it to a PC spec by spec including you GPU, screen spec and apple warranty and after care.
PC is better for gaming, upgrading parts is mostly a DIY.
iMac is great for photo/video storing and editing, more stable (I am running 3D software and I experience less problems running multiple programmes).
The apple customer support is priceless.
Enjoy what ever you get
There is much more to it (I only had it for 3 weeks)