Hi Eduardo,
For me, the hair as you had it previously is more characteristic and how I picture him, but either is equally as accurate. I just like the first style better. The important aspect of the beard IMHO is its coarseness as much as length, but I do think the longer beard would be more conducive to making it suitably scrubby. Also, I was playing around with the picture of Lincoln and the straight ahead shot of yours, laying one on top of the other and fading it in and out, and one thing that popped out was the missing whiskers on the sides of his face, between the sideburns and the beard.
Cheers
Jason