Everyone is different. We can't tell you firmly which is best. I have redeemed 50k miles for domestic travel in the past (not AS miles, mind you), because it was the only itinerary that worked, the cash fare was on the high side of $700 and I already had a home renovation or big car repair going on that month, etc. But as a rule I prefer to redeem my AS miles at the saver rate only for transcon travel... and premium cabins for overseas travel on partners. I would tend to pay for the ticket you're looking at.