I have a 5550. It's a nice machine, replacing a 932c (which now lives with
my soon-to-be sister-in-law). You can change out the black 56 cart for the
58 photo cart which pairs with the 57 tri-color cart for 6-color photo
printing (PhotoREt IV). With just the 56 black and 57 color carts it prints
in older PhotoREt III mode, which is visibly inferior to the new 6-color
printing...especially in skin tones. It's amazing.
I just leave the 56 and 57 in, and change to the 58 when I want to print a
photo. The 56 black cart gives excellent results on both multi-purpose and
premium inkjet papers, rendering razor-sharp text.
I would definitely pick the 5550 over the Lex Z45...it's a noticeably
flimsier machine than the HP, it feels like a toy. The HP's a lot more
robust (though the new HP's aren't the indestructable tanks the earlier ones
were).
HTH
TP