Having jumped into full frame goodness a couple of months or so, I'm really chuffued to bits with the results I'm getting. Marrying a full frame body to a fast prime lens offers a real quality for the price I've paid for them.
The real advantages of going full frame are for each to decide. No one can say yay or nay to one or the other, it really is horses for courses at the end of the day.
Looking at images I've taken from my 5Dc what I am liking is the following -
Reduced Image Noise Full Frame sensors on the whole handle noise from images much better than a crop sensor. As a full frame sensor contains larger pixels it collects more light, and therefore offers reduced noise, thanks to the way it deals with the signal of light. This means you can push that little bit harder with full frame than you can with a crop sensor.
Quality of Image In part, thanks to less enlargement a full frame image will offer better quality than the equivalent crop image. If you are looking at smaller sized images, the quality maybe marginal, however on larger prints, the full frame camera certainly comes into its own.
Lenses at their actual Focal Length With Crop Sensor Cameras having a variety of magnification (in my case with a Canon 40d - 1.6 crop factor), the choice of lens is often dictated to by the crop sensor, and not me. For instance, if I want to shoot at 50mm on my 5Dc, I pick up a 50mm and shoot. If I do likewise with the 40d, I am actually shooting at 75mm. OK, so it maybe a little disingenuous but I like shooting at the required focal length.
To the outsider, these points probably sound quite confusing and to the seasoned photographer, they will have their own thoughts as to crop v full frame.
At present, I feel I am where I want to be in the crop/full frame debate and loving it!