MacBook Pro 17" vs 15" Retina Display for Photoshop work

My photo travel laptop is a 17" MacBook Pro. I'm considering upgrading to the latest MacBook Pro but the largest screen size currently available (or likely to be available in the future) is 15", though at much higher resolution. I'm wondering if anyone has made the downgrade from 17" to 15", and if so what do you think? Is the new 15" display equal or better to the old 17" for working in the hotel with Lightroom and Photoshop?

Note that my primary concern is the usability of the UI, not the resolution of the photos themselves. Lightroom and Photoshop are both screen hogs to start with. They feel cramped even on the 17" compared to my 30" monitor back home so I'm worried that the 15" may work less fluidly than the current 17".

The problem with Retina display is that the image becomes really small when working in native size. Many programs scale the photos by interpolation to make it appear larger on the screen, this makes fine details look coarse and judging sharpness very difficult.

Retina is great for reading text IMO but it is not great for critical processing and dealing with photographs IMO. you should try it in an Apple store before buying.

I just returned my macbook pro retina. Not for me for sure. Nice specs. But found photo editing was not to my liking at all.