I prefer U1 though U2 is very cool.
I prefer U1 though i don’t use dash forward ultra.
I prefer U1 though though i suck with my input and timing and my opponent always fall behind me or i whiff a toward mk -__-.
Si in my game i don’t have the opportunity to use Ultra 1 often but i don’t care.
What i like in Ultra 1 is : Fullscreen teleport and Startup 7 frames.
Believe me at high level, it’s not easy for chun li to hit with cr lk and follow it by ex legs and ultra 2.
When your opponent is not a scrub, he know the threat of the cr lk.
Good players don’t jump like that to eat freely the new loved Ultra 2.
So your opponent can shutdown your game with close fireball, ambiguous jump in, and random tatsu at mid range (ryu example).
Ken can do a ex tatsu to escape an ultra 2 punish if he jump.
Deejay and Guile don’t need to jump. They love stay in crouch position so don’t expect hit them with cr lk often.
Akuma has many setup with his fireball at any distance. He can fireball, let you jump and punish you with a demon flip when chun is in the recovery landing so she cannot do anything instead block. So akuma has a free demon flip throw if he is smart.
In fact with U2 you don’t lead the game versus shotos.
You have two options. Kill them fast or you will die slowly 
With Ultra 2 you need to close the distance so smart people will run away from you as soon as you meet them ( jump tatsu, jump back fireball, cross up when they are in the corner and you approach them, etc)
I think i will use u2 versus chun li to punish a reversal ex sbk after a succeed safe jump
It’s possible with ultra 1 but the timing is tricky ( you need the charge).
Versus Gief, if i can punish a blocked lariat with U2, i will go for it.
Again it’s possible with ultra 1 but sometimes you lose 
Versus Rufus i use Ultra 1 just because i can punish his cr hp. Don’t forget you can punish the sweep of ryu.
At this moment i prefer work on some setup to bait a sweep or any move instead of pray for my opponent forget to block a cr lk
You can punish Mk, HK and EX Double Rolling Sobat of Deejay on block with your ultra 1
And the good thing is the “safe” version is easy to recognize ( only one hit)
Others things : The damage with ultra 2 in combo after ex legs is 370 (if i remember) when your ultra is not full ( 1/2)
Use your ultra 2 lovely charged during the first 20 seconds to add “only” 150 damage, i don’t think it’s worth it.
Of course is this extra damage can kill them ok. But if not ?
Look the strategy of boxer players. They keep ultra to kill because until they have them, they represent two threat : Juggle damage and fireball punishment.
i’m thinking about use Ultra 2 versus Blanka because what is the point for blanka to rolling attack chun li when she have ultra 1 ? For chip damage ?
Blanka can chip for free with electric thunder blockstring all day.
and when you wait in charge, he use a short rolling attack and stop just fornt of you.
I prefer punish blanka after a blocked ultra 1, blocked backstep roll or whiffed vertical roll with the new ultra 2 of chun li when blanka is still airborn (recovery)
