As long as you eventually use all of the HSA funds for qualified medical expenses, the HSA contribution might be better, assuming similar investment options. $5,300 in an HSA contribution saves the income tax on the $2,700 difference between $5,300 and $2,400 put into the FSA. If your combined federal and (assuming you are not in California) state marginal income tax rate is greater than 600/2,700 or about 22.2%, you will save more in taxes than the $600 that you lose by not having the HRA.
Timeframe is irrelevant.
