Originally posted by Trickortreat 1. AF can be made equal
2. FPS can be made equal
3. metering can be made equal
4. lens focal lengths and light gathering can be made equal
5. high ISO difference is so small that isnt really relevan
6. how much thin DOF do you need? A 85 1.8 on crop is borderline usable
7. there were billboard size prints made with D1, i dont think much more resolution is needed anyway.
Slight advantages of FF are really extreme niche. General use photography is better suited with crop.
If you can't see the difference between the two formats then you've saved a bunch of money.
At this point APS-C is "good enough" for many people -- probably better than most people need. APS-C actually tends to have an advantage with regard to frame rates and tends to have more depth of field for similar framing. I'm not sure about your earlier post about the D750. The D750 was released in 2014, but it was based on the sensor in the D600 which came out in 2012 -- pretty old by today's standards. D810 is probably a better comparison and it shows about a stop distance through the range.
If you look at it, you will see about a stop difference with regard to noise and dynamic range between APS-C and full frame sensors of similar generation. This isn't huge, but it really does make a difference if you are shooting dark venues and need iso 12K to freeze performers or if you shoot landscapes at sunrise and want to be able to capture nice tonality in both the sky and the foreground without taking multiple images.
As far as thin DOF goes, the issue tends to be finding equivalent focal lengths. DOF with an 85mm on APS-C is going to be thin, even stopped down, but if you use a 50-ish mm lens on your APS-C camera to limit working distance and emulate you 85mm portrait prime on full frame, you find that it is a lot harder to get that narrow depth of field that you are wanting. And many 50mm lenses need to be stopped down a bit to get sharp, meaning you will struggle a bit more if narrow depth of field is your goal.
On the wide angle side, there are a lot faster lenses available for full frame camera than for APS-C. This can make a big difference when shooting the night sky and is why folks who do much astro photography gravitate to full frame.
To me, there is a big difference tonality between the formats -- bigger yet between a K-1 and a 645z (which I can't afford). It shows clearly in images I have viewed here and on Flickr, even at web sizes. APS-C images just feel "pushed" a lot quicker. For many images it isn't a big deal and I said before, APS-C is probably more than enough for most photographers. I could get by with it, but there is a reason why I prefer my K-1 to my K3 in most situations.