> around 44ms and 206ms
so around 162ms difference per 100,000 elements. This doesn't concern most of us for anything less than 1,000 elements (1.62ms).
I use querySelector more often simply for aesthetics (consistent with other calls and qsAll).
That said, the fact escaping is necessary could point to part of the reason why querySelector is slower. There's obviously some additional parsing necessary just to work out what the developer is requesting. If you don't need to spend that CPU time then it's certainly better not to.