Welcome to mac world.
Best thing we ever did. Our iMac is now six years old and unlike every PC we ever had has given no trouble.
Grab yourself an el cheapo wireless mouse so you can use right button if your mac mouse doesnt have it. Makes life easier.
Also, if you have an old monitor grab the cable to connect it to the iMac and run it dual screen. Just plug it in. It asks whether you want it on the left or right - thats it!
If you need office you can get office 365 for a yearly fee and is works on up to 5 computers. Office in Mac seems to be a little behind PC but is fine.
We run a 4TB external hard drive and store all the movies and photos on that and use Apple TV ($100) to stream them to our TV. The kids download the movies to their two Ipads and two iPods as well as our three iPhones and the MacBook Air. We travelled from Tasmania to Qld and they had more movies than they could watch.
Yep we are an apple crew now!
This will join us at Xmas -
https://www.apple.com/au/mac-pro/ENJOY!