Thanks George..well you seem pretty sure, why would that be?
Robin
Hi Robin, First of all I use Nikon FF gear extensively for a lot of my professional duties and have done so for many years so in no way am I against Nikon equipment I am only comparing the two cameras you have quoted.
I have not been the owner of a D5100 but a member of our staff had one and at the time I had an X-E1 which he has since bought from me to replace his D5100 and I have upgraded to an X-T1, (I'm also lucky enough to have an X100s and an X-20).
During this time I had tried the D5100 both outside and in the studio with pro grade glass attached and the end results were very good indeed as you would expect from Nikon, but shot for shot they were no better than the X-E1.
The focussing on the D5100 was slightly faster than the X-E1 even with the very latest firmware update for both body & lenses.
The battery life is better on the D5100.
The Nikon flash system is better (Fuji are lacking in this department but apparantly there are things coming out soon from other manufacturers).
There's probably one or two other things about the D5100 that could be thought of as better than the X-E1 depending on personal taste.
The X-E1 has more Micro detail in the images than the D5100.
The X-E1 appeared to have more dynamic range in the images at comparable ISO settings.
The X-E1 had less noise and the images were sharper at comparable ISO settings, although it has been said that the Fuji ISO settings appear to be a little inflated but I have not noticed this.
The X-E1 is smaller and lighter to carry, and is quieter to use than the D5100.
The Fuji lenses are optically every bit as good and in some cases better than comparable lenses from Nikon. I can't compare them with other manufactures lenses as I've never used them.
For me the X-E1 plus points outweigh the D5100 plus points.
But please note this is only my opinion and obviously other peoples opinion may differ. We are all entitled to our own opinion.
Hope this helps.,
George.