Not me. I have never bought Avios and don't intend to start now. I tend to spend them as I earn them and don't accumulate. If I don't have enough then I either wait until I do or else I book a cash fare within my means instead.
In terms of the OP's dilemma whether to buy or not, why not consider flying in J both ways, or - perish the thought - consider PE and J instead? Provocative I know, but as my mother would say, "cut your coat accord to your cloth"