Apparently most of us prefer the digitigrade legs. 

When I think of Ferals seamlessly switching modes, I think of werewolves in Skyrim. They fairly easily go from two-legged walking to four-legged running. 

One person said that if they're kicking then human-like legs make more sense and I disagree. 

Think of a kangaroo, they balance on their tails to kick. 

Cats use their front legs to hold onto something, then use their back legs (and claws) to rip into them and can then easily let go and run away. 

Since dogs lift their legs to pee on things, it's not hard to imagine their knee extending a bit to kick their opponent. 

Just a few examples off the top of my head how even with digitigrade legs the ferals would have no trouble fighting.

Judging just by the picture above, digitigrade version does look better and fit the name 'feral'. But, if mode-B gonna fight like a human (punching, kicking, or using melee weapon), the humanoid legs makes more sense. 

The digitigrade legs not only look more badass, but I feel like it would lend itself nicely to the "feral" name. Idk, I think it looks more lethal and dangerous. Also, since the digitigrade legs in animals tends to help them run faster, it would make more sense when you transition into mode B for speed. 

I think digitigrade version looks a bit more fun. Maybe it's about the feet on the left version being a bit flat and more like they are bended metal sheets, rather than joints or something. That's how I see it anyway. Also I'd say I just like the version on the right more overall. Don't know if it's just me, but it seems like you gave it a bit more thiccness, like the shoulders are a bit rounder and wider, the neck looks thicker, thighs too. With all that plus the legs being animalistic, the right one looks more menacing to me. Not and expert though, so just stating my opinion