I use both, though they work pretty much identically. There is focus peaking available, which helps you pull focus on video much more accurately on a small screen, though you can get a deep DOF in next to no light if you want, also. That takes some getting used to—you're like, I can do what?
As far as I'm concerned you can go ahead and believe the hype. The main drawback is that it's 12.2 MP, but unless you're making murals that people walk right up to, who cares. With an HDMI recorder you can shoot 4K, which is bananas. The A7S is now an "old" model—like 3 months out of date—so you can get some deals on eBay. I got a $50 adapter and use my Canon lenses; the AF isn't spectacular that way but I hate AF anyhow.
@330CK Ah yes, film. I'm mainly interested in cinema, and went to film school in the last "glory days" of analog, so I have absolutely zero nostalgia for celluloid. To make a 20-minute 16mm narrative short with no commercial market whatever, you were looking at $15,000 just in processing costs. And those aren't constant dollars, either.
Obviously for stills film makes a lot more sense, if that's the way you like working. But when I started out, all of us would have gleefully murdered a human to get usable, much less gorgeous, ISO 27,000 on ANY camera—that was like contemplating time travel—so it's amusing to watch people kinda just go, "meh."
Ah the glory days... pushing 1600 ISO black and white film to 12,800 was the bees knees. I worked in a pro photo lab back in the day, and used to just wonder what some of those photogs were smoking. Actually, it was obvious... This was Santa Cruz after all.
I love film, and have pondered pulling my old Bronica 6x6 camera (SQAi with a 120 back) out of retirement, but the damned convenience of not waiting for processing (or heaven forbid setting up a darkroom in my basement!) keeps me choosing digital. I can make digital prints look film grainy anyway... Gotta love that Photoshop CC!