How much screen on time does the iPhone get?

You really can't go by screen on time. What kind of work/play etc do you get done on your phone? Playing a movie will obviously use up more battery than reading a text document.

That being said working two jobs with one involving me pretty much constantly being on the phone, I get about until 6PM, before needing charging, I wake up at 6:45AM.

I'm also
-Tethering
-VPN access for RDClient
-LMI Ignition
-Calendaring using Exchange a lot.

Second job is Walmart, but even then my battery is already drained from my first job.

It's pretty difficult to answer that question.

I get 5-7 hours of USAGE. I'm going to assume 1-2 hours of that is screen off time usage. Like phone calls, email fetching, etc. And included in that 1-2 hours is inadvertent screen on time like when you get a text.

I could never get an entire day out of an iPhone with my usage patterns.

Battery life appears worse on iOS 7.

They seem to waver between having great to mediocre battery lives. It was great on the original iPhone, pretty bad on the 3G (mostly due to 3G and GSP eating up the battery despite Apple's claim that it has modestly better battery life), back to being great on the 3GS and so on. Nevertheless, I've been able to go through the entire day without recharging on all of them.

Define great.

Also, cell signal strength is another huge battery drain- so, if your carrier doesn't have decent coverage where you are, it doesn't matter how long the screen is on or off for.

I've done some tweaks to make the battery last longer on iOS 7.

-Turning off Background App Refresh, Honestly I haven't noticed ANY difference at all by having it on, the apps seem to refresh on startup anyway, such as Facebook. But I DID notice a battery difference having it off.

-Turning off Location Services for random things like iAds, and turning off recent location tracking.

-Turning off the fancy parallax effects.

-Turning off Ask to Join networks on Wi-Fi (off by default, but check to make sure you don't have it on)…I leave Wi-Fi on though, just to simplify things when I need to print using AirPrint etc.

-Turning off Bluetooth, while also turning off AirDrop & iBeacons. I turn it on when I think a store is using iBeacons just to see it work.

By doing these alone, I finally got a days worth out of my battery. Too bad now I feel like I gimped all of the nifty features of iOS 7. But its either that or an ugly Mophie.

In excess of 6 hours with 1 day 4 hours since charge. Have had a little better but it doesn't differ too much from that.