iPhone 5s: Which consumes more battery, 4G, or 4G LTE? Under Settings > Cellular, there's an option to enable/disable LTE. When disabled, my phone reverts to 4G, as indicated by the icon in the status bar.

I've read elsewhere that using 3G causes greater battery drain than 4G (in fact, Apple's own iPhone 5s spec sheet indicates that you only get 8 hours of 3G data, versus 10 hours of 4G LTE data). Which leads me to the following line of thought...

If I disable LTE and revert to standard 4G, what is the effect on battery life?
"Standard 4G" is kind of a meaningless phrase.  According to this article, disabling "LTE" means it's limited to either CDMA 3G or HSPA+.  HSPA+ is supposed to have performance comparable to LTE, so I would guess that if you disable LTE and see a "4G" icon, it means you're getting HSPA+.

PC Mag confirms that Apple (like their competitors and partners) started using "4G" to refer to any post-3G network, like LTE, WiMAX, and HSPA+.

Anyway, most of the articles I've found comparing power usage between HSPA+ and LTE suggest that LTE has slightly lower power consumption, but it seems to be a pretty small difference.  The signal strength where you are located probably has more impact than this setting.  Early LTE phones apparently sucked a lot of power even when idle, but with newer phones this seems to have been improved, e.g., this iPhone 5 user claims battery life is "nearly identical" whether LTE is enabled or not.

So you can try both settings and see which works better for you, but I wouldn't expect a huge power savings.