cubshopper,
In my opinion you should go with the 1050. I own one, and it's doing a great job. You don't mention which 1554 you're looking at, the SLT 1554 or the GT 1554, the GT 1554 has a thicker deck and bigger wheels/tires than the SLT 1554. In either case, for the money, I still take the 1050. Oh yeah, the 1554's have the "high back" seat, the 1050 just the "standard" seat, although mine is quite comfortable.
Longevity-wise, I think most here will tell you they are equivalent, with the exception of the slightly thicker mower-deck on the GT 1554. As far as I know, bigger wheels and deck don't add up to longevity, welded-frames, quality engines, and heavy-duty transmission, axles, spindles, etc...do, and the 1050/1554s are about equal there. If you really want increased longevity, you need to jump to the 2xxx series (or take really, really good care of your 1xxx-series).
See my post on why I decided on a 1050 over a 2544 here also:
http://www.tractorbynet.com/forums/showflat.php/Cat/0/Board/cubcadet/Number/635760/page/3/view/collapsed/sb/5/o//fpart/1
Thanks,
mike@slavis.com