Buying advice? Macbook Pro or iMac

My Macbook Pro Late 2011 finally gave out on me so I'm looking to purchase a new computer.

I know I am going to get another Mac, but can't decide between these three:

iMac 2017 21.5 inch

Retina 4K

3.4GHz processor quad core Intel Core i5

16GB 2400MHz memory

512GB SSD

Radeon Pro 560

iMac 2017 27 inch

Retina 5K

3.4GHz Intel i5

16GB 2400MHz memory

256GB SSD

Radeon Pro 570

Macbook Pro 15 inch

2.2 GHz 4-core Intel Core i7

16GB 1600MHz memory

256GB SSD

Intel Iris Pro Graphics

I am a photographer/videographer so I use Photoshop, Premiere and After Effects a lot. I understand the importance of having 16+ gigs of ram and SSD over Fusion. I would prefer to get the Macbook Pro and then purchase and external monitor, but I'm unsure of 2.2GHz processor vs. 3.4GHz? Will that hinder performance much? Also how good is Intel Iris Pro Graphics compared to Radeon? The big thing is I am trying to keep price $2000 and under.