MACs have always been traditionally used more by graphics folks, since they have better graphics and displays than most PC computers standard.
The computer also comes with iPhoto, which is photo manipulation software. I have not used it, so someone with experience with it can give you more advice on that. There are also a good many photo and graphics programs made my Apple for their systems.
I too have been a Windows guys for the last 12 years and plan on getting a MAC in the next year or so, primarily because I am sick of fighting Windows updates and software glitches, but also because as I get more into photography, I think it will handle the memory requirements better than my laptop.
As far as learning curves, if you purchase your MAC at one of the Apple Stores, they can assist you with classes, help you transfer your data from your old Windows computer to the new one, and pretty much anything else you'd want to know. You can schedule appointments with them, so you can do it on your time and know you will have someone there that knows what they are talking about, instead of having to take your chances like at a big box store.