Real devices yes! I tried to use emulators a couple of times, but the first few attempts failed due to Instagram detecting it (missing cameras, etc.), and later attempts failed when I realized it's not going to save me a lot if I went the emulator route, because they need quite a lot of resources too, and you can't just run 10 emulators on a regular computer unless you optimise them extremely well and know what you're doing (custom Android build as a minimum). So it actually turned out to be easier with real devices. Plus, there's been some IP/VPN/Proxy emergencies, where it was super handy to pop in a 3G/4G sim card into the phone, and have it work 100% like a real person's phone. The cost is considerably higher (~ 15-50 GB per phone a month), but I am still looking into doing that, as it would allow the "phone agents" to become completely independent from location.
Buffer: I haven't done much in terms of "battling" with competition, simply because my users will tell me what they want, and that's an easier crowd to serve than trying to follow a competitor who may be running down the wrong path without knowing yet. If a bunch of users ask me for the same feature multiple times, then I look into what it takes to make it happen, or I'll explain why I can't offer that, and that's what's been driving it from day one.
Thanks for your note about the typo, I am actually always a bit ashamed of my landing pages, because they feel the least fun to make (to me at least), when they drive most of the conversion of course.