Time to purchase new computer: advice?

I am running Articulate Storyline 2 on my MacBook Pro via Parallels Desktop 10 for Mac. I do a great deal of moving back and forth between Articulate on the virtual machine and Adobe Photoshop on the Mac. The only problem I have is that sometimes things move a little slowly.

Here's my challenge/opportunity: my company will purchase a new computer for me this year, and I want to make sure I get what I need. I am thinking of moving from a laptop to an iMac to get greater performance. I have read some posts that reference problems with a retinal display. Should I avoid a retinal display?

To complicate things further, the folks in my department who just purchased Storyline 2 didn't get Parallels. IT installed VirtualBox instead, and they haven't figured out a way to quickly and easily share files between the two systems. I'm thinking that IT may install VirtualBox on my new computer instead of Parallels and not sure how this affects the Storyline experience.

If YOU were buying a new Mac right now to run Storyline, what would you get? I appreciate any advice you can pass along! Thank you!