Pretty good deal. $1650 for a longhaul U seat (90k+10k from your account). Or a nice dent of miles toward a longhaul Z seat.
Of course, the one major disadvantage is that if you BOUGHT a longhaul J ticket for $1650 cash (which is not unheard of in this day and age), you would earn EQMs/RDMs/COSBonus/segments for those flights. Buy buying the miles, all you earn are 2,063 RDMs from the purchase, assuming you use the Starwood AMEX (1.25 miles per dollar).