Other than to true Trump supporters I don't think "Lyin' Ted" stuck except to the extent it was so outrageous that it was taken as a comment more on Trump than Cruz. I thought it was unwarranted, and pretty sickening. One of many bad Trump moments.
"Low-energy", on the other hand, resonated with anyone. Still a rude, nasty thing to say, but aptly descriptive.
As a Cruz supporter, every time I saw the "lyin' Ted" crap, frankly, it pissed me off.
I knew where it came from, as Trump will give derogatory nicknames to anyone he considers an adversary:
"little Marco"
"Dopey Prince Al-Walid" (in a business deal)
"Crooked Hillary"
But that says something aobut someone who is running for President. What's next? "Poopy Putin"?
Hardly the sophistication or demeanor one would expect from Presidential material.
As for Cruz being "low Energy", I think there is a difference between being reserved in demeanor and 'low energy'. No one who is out campaigning, running a grueling schedule is (of necessity) 'low energy'. Having a composed and adult demeanor, someone who my grandmother would have felt had good enough manners to be in the parlor, so to speak, is not something I see as a negative. Proper decorum would be nice for a change, considering the current occupant of 1600 PA Ave slapped the Queen of England on the back.
Note, too, that Ronald Reagan spoke calmly, even when angry, and you will see what I mean. This is statecraft, not WWE. Jumping around like a poorly disciplined child may impress some, but it would not play well with heads of State elsewhere, and for all the 'energy' Trump displays, it is voiced as disjointed sentence fragments and incomplete thought trains instead of a directed and coherent mental process.
Beyond one liners, he frays, and I don't see that as a plus.