it will be untethered, I am still on 5.1.1 as well with my 4S
I dont know of the headache you speak of, but I have never had one issue with anything that I have installed. I always use the mainstream created apps that are well known not some poorly coded app. There are some that I use multiple times a day.
Folder enhancer allows you to have pages inside folders along with 16 apps per page
SBsettings allows you to turn off and on settings quickly by swiping the top
I have a ton of tweaks in the notification dropdown like flashlight, clear all running apps and other toggles which is also accessible without even unlocking the phone
Bitesms texting app allows for better integration of messages
I could go on but those are the major ones, have never had a single issue in the years I have been doing it, if you need any advice on anything just let me know. I would be glad to help!