I picked up the HP M553 while it was on sale at Best Buy, and there was an HP special running on buying the toner with the printer (20% discount) so I picked up one of each. I decided to go with the lower toner capacity level, as the higher level was not as discounted, and for my use a full set of spare cartridges should last for a number of years.
The new toner design is suppose to have a notable effect on cost. First the power consumption specs are down, and I can say there are no light flickers when the machine warms up (as this did for the smaller Samsung printer). And the idle power level is also much lower, but again it has a super fast warm-up and first page print from idle. The toner cartridges are expensive (especially for home use), but the new toner design is suppose to produce more pages and reduce the per page cost (and if specs hold up should make this a lower cost printer over its life).