IMHO, comparing efficiency on something like that is not worth the trouble. The difference of a few micro seconds won’t matter until you’re doing that at very fast rate (which you’re not since you’re doing this operation on messages). I always advice my student to focus on readability vs efficiency.
Also if you want to compare the efficiency, you might want to do the operation more than once, otherwise you measure mainly the rest of the patcher than the specific object. Using uzi 10000 gives a better idea.
#2 js is faster, but runs in low priority that’s why you need to wait for the process to be done, in order to trigger the next thing (see the extra outlet)