Z77 is way latest version for 2nd gen intel CPU chipset compare to B75. Z77 also compatible n ready for your Ivy Bridge and should support above 2200MHz DIMM speed. i myself had a problem in reaching 1600MHz for my dual channel corsair 8GB, 1600MHz RAM. when the B75 only support only to 1333MHz memory speed. where the only solution is to change to a z77 or z68 chipset motherboard. money again. But it's really such a waste to use a B75 chipset on your i5 3550.
n i think (not so sure) i5 3550 won't support XMP (intel extreme memory profile) for memory OC bonus from intel. need at least i5 3570K. just differ by $22 approx compare to i5 3550. plus u can do OC on i5 3570K in the future.
As far as the difference goes, B75 doesn't do memory overclock, that's it.
Simply not true
I have an Asus brand motherboard with the b75 express chipset that can run memory up to 2200 O.C. and supports XMP profiles and can also overclock the CPU and GPU provided I am using an overclockable CPU.
and the best part... it was less than 100 dollars from newegg with shipping