Saddle differences

mobilis
mobilis Posts: 65
edited May 2009 in Road beginners
I'm reviewing these saddles:

Selle Italia SLR Trans AM
(http://www.bike24.com/1.php?content=8;navigation=1;product=518;group=34;page=1;pid=37;menuid1=4;menuid2=0;mid=66;pgc=0;orderby=2)
and
Selle Italia SLR Gel Flow
(http://www.bike24.com/1.php?content=8;navigation=1;product=2820;group=34;page=1;pid=37;menuid1=4;menuid2=0;mid=66;pgc=0)

1) Same model (SLR) both with cutouts. What's their differences?
Different padding maybe, due to different weight?
2) How long do these kind of saddles last?

Thank you.