I leased my LEAF for two reasons.
1: Less debt.
We needed a car for me and my girlfriend, we traded in two cars and got one so that she could sign for a house. I can't sign because I started at the Nissan Dealership here in Utah a few months ago and have to have 2 years of commission work to be able to co-sign and have an "Average Income". Anyway, she had over 6 grand in negative equity, so a lease helps us out there (in 2 years, all that neg is gone). We got the huge debt for a cheap car out of her name, and I only have one car under mine.
2: The technology is rapidly improving compared to internal combustion engines.
Just between the 12 and 13 model years, you have a slight increase in overall range, and a sharp drop in charge times with that 6.6kw onboard charger on the SV and SL models (yes, I am a car salesman who knows the Leaf well enough to actually inform, not just sell. we have 4 of our sales people here who drive leaf's. not including the 5 others in shop, service, and accounting who also drive leafs). After the first month I realized I'm not going to have much range anxiety, and I know that from experience showing me I could go another 12 miles when my guess-o-meter dropped to dashes after saying 9 miles left. I'm more confident with actually using the climate control, and I know I can average about 2 trees in a 20 mile round trip if I need to drive economically. Otherwise, I'm enjoying my car by taking turns fast, feeling the instant torque put me in my seat, and enjoying the quiet ride through the lovely Salt Lake scenery.
On a random note, I've gotten into the swing of selling cars, so I've started to look at the Zero motorcycle brand. Interesting stuff going on over there...