From my experience as a iPhone user since the 5 and jailbreaking for years. I have purchased the iPhone X (I skipped the 5S, 6S/6S+, 7/7+, 8/8+). Only thing that kept me purchasing a new iPhone every year was "Oh great jailbreak won't be out for who knows how long". Back in the day Apple didn't really know about it, but they found out and damn did they attack it.
That aside, reason why I got the iPhone X.
SwipeSelectionPro: As a lyricist, this is very important to me, I type a lot and I need to get my lines out as quick as possible before I forget them so if I get a typo, I swipe back and fix it - not hold down and wait for the bubble. Alternative to this has been a feature since force touch on the 6S where you swipe and it moves the cursor.
Swipe Home, SwitcherCC: For years I've hated the home button, I don't wanna click it a million times, swipe up and I get control centre and app switcher at the same time. Swipe from the right side of the phone to the left and it acts as the home button. iPhone X swipe from bottom = go home. I love how the Apple fans are like "omg we can navigate our phone with gestures now omg" and I'm sitting back like "uhh yeah I've been using my iPhone like that for years lmfao"
DoubleTapToSleep: I don't wanna click the sleep button, but sadly iPhone X, I will have to.
There are many more jailbreak tweaks I love, but can give up the others as the keyboard and gestures were my most prioritised tweaks. Keep my iPhone SE as my jailbroken phone, and have the iPhone X as a normal up to date software phone.
Others probably said it but Reachability is done by swiping downwards on the home area twice-quickly.
A jailbreak tweak for control centre, could probably hold down on the home area for it?
Unlocking straight to the home screen is a working tweak by a third party app, if no notifications are on your screen, it'll unlock straight away.