Until Atom can open multiple large files without slowdown, or very large files without just crashing, I don't see it as being a threat to Sublime.
They are definitely doing some great stuff with Atom for a free product; Sublime will maintain it's value as a paid product until there is full parity of features.
"Twitter Firehose for iPhone" is really a misnomer. There is no way that this is a true implementation of a realtime feed of the full Twitter data stream...
It actually really is what the title says: you can have a look at the public Twitter Streaming API here [1].
Obviously you won't receive 100% of Twitter's Tweets (I dare any iPhone to receive every Tweet that contains the character 'o' in real time, for example) but as many Tweets as Twitter Servers decide to send you (depending on multiple factors, not publicly known, but I guess your connection speed is one).
Also you won't receive 100% of the Tweets because you have to pay Twitter for that service. Still, you'll get plenty of new Tweets live: just give it a try! It's quite cool to see it in action [2].
I'm happy to answer to any other of your concerns :)
Only $900? My partner and I are both under the age of 50 had to pay over $1200/mo this year for a personal plan with BCBS without ridiculous deductibles. This was an increase from ~$1100/mo from just 6 mos ago.