The Galaxy S5 Active isn't a bad phone, but it's not different enough from the regular S5.
Every new Samsung flagship is quickly followed by a shotgun blast of variants, in keeping with Samsung's "flood the market" hardware development strategy. Develop a flagship phone to appeal to most people (this year, the Galaxy S5), and then follow it with similar-but-distinct phones to fill every possible niche.
Enter the Galaxy S5 Active. We liked the Galaxy S4 Active when we reviewed it last year, mostly because it added some much-needed sturdiness to Samsung's slippery plastic and because it was waterproofed. While it had most of the same speedy internals of the S4, it also used an LCD display panel instead of AMOLED, a nice option for people who don't care for the latter screen technology. In short, the S4 Active was different enough from the vanilla S4 to be worth a look, but not so different that it lacked all the S4's most appealing features (a problem with variants like the S4 Mini).
But the Galaxy S5 is already waterproof. Its back already moves away from the smooth, slidey plastic of older Galaxy phones. AMOLED screen technology has improved to the point where it's not really any worse in direct sunlight than an LCD screen (and the S5 Active includes the same 1080p AMOLED display as the regular S5, anyway). Is this year's Active variant still worth a look, or will most people be better served by the standard S5?