I've recently made the leap to a "full frame" DSLR and have invested in new Nikon D750. The Nikon D750 is a professional FX-format DSLR camera that is fast, versatile, and agile. 
The term ‘full frame’ refers to DSLR cameras with an image sensor the same size as a 35mm film frame.
Most enthusiast photographers use APS-C DSLR cameras or micro-system cameras (MSCs) because they are generally more affordable, not to mention smaller and lighter than their full-frame counterparts. However, a full-frame DSLR has significant advantages, which arise because the image sensor is larger than that in APS-C-format or micro-system models.
The larger sensor surface area also means that more photosites can be used. A larger number increases the resolution, which will therefore produce more detailed images.