Based on other people's experience here, I'd lean towards the IPF8300 in a dry environment (or you can do what I do, and keep the Epson in a humidity controlled environment).
Also, the IPF8300 comes with a lot more ink than the Epson (and by all reports, wastes less of it on cleaning cycles).
Of course there's more factors than that involved, and there are enough threads on this forum to keep you busy for some time!
At the prices you're being quoted, you really can't go wrong either way.