The Intel i5-3470 will work absolutely fine with the B75 board you have picked. However since that Gigabyte Z77 board is on sale you should go for that. Either board should work fine. Both boards should accept that CPU w/o a bios version upgrade.
I call the B75 as the casual board used for businesses and stuff like that. The Z77 on the other hand is what I call the enthusiast's board who likes overclocking and utilizes all those nice features on those boards.