Due to the huge increase in pixels being pushed, the retina model has to spend more energy on a GPU and in some circumstances might not benchmark as well as the non-retina model when a high frame rate is needed. Finding a conclusive measure will be hard since personal sensitivity to "lag or tearing" when scrolling or gaming means that something that is totally unacceptable to one wouldn't even be noticed by another. There will be no substitute for hands on test driving or buying from someone that will accept a return if you can determine a mistake in estimating your needs soon after purchase.
The hardware features are far less subjective - clearly any or all of the components that no longer ship could be seen as viable reasons to purchase the non-retina 15-inch MacBook Pro:
- Security slot
- Integrated optical drive
- Line in and out (in addition to the headphone jack)
- Integrated Ethernet
- Integrated Firewire
- User-replaceable/upgradeable and Physical Hard Drive (as opposed to solid state)
- User-replaceable/upgradeable RAM
- Glass protected LCD panel
- Physical size of the MagSafe connector or the body itself
Missing these components is amplified if you already have accessories or manage several computers that are pooled and expected to be the same physical size. For most, these omissions when selecting a retina MacBook Pro are a welcome change as adapters are available for most of the connections that are lost. Subjectively, if you don't need the resolution or weight/performance that the retina model allows, any of these considerations could tip the scales to make the non-retina model preferable. In my experience, the added screen protection and the known strength1 of the non-retina model as well as the ability to upgrade RAM/storage are the primary reasons people have passed on a retina model thus far.
1 - It's too soon to know if the retinal model's design is more, less or equally as rugged as the 15 inch MacBook Pro, but the existing design is extremely strong and I have seen them survive falls from a moving car roof at 40 MPH with no protection and only cosmetic damage. I have also seen a short 10 inch fall do $1300 damage to case, logic board and LCD panel even though most drops from less than two feet do anything but cosmetic and light bending of a Pro. Even with that variability in damage, the Pro are clearly more stout than the Air line so if you are hard on your hardware, the added bulk of the non-retina model might be a good reason to prefer it.