Probably a decent deal. If you're diving in the USA or Caribbean you'll have to either buy a DIN to Yoke adapter, or convert the regulator to yoke.
When buying any used regulator, it's very important to have it serviced - then again every year. Most shops charge somewhere between $75 and $150 for servicing a regulator. That's not specific to Zeagle or the Flathead 7.
The Zeagle Flathead 7 is not the current model in that line. It's been discontinued and replaced by the Flathead 8 which sells for just over $600 new. Usually you have to buy an octo and SPG in addition to that price. The fact that it's been discontinued doesn't mean it's bad, though.
Before you decide, figure out if there are any dive shops that will service Zeagle regulators near you. If not, you'll be mailing it away every year. I'd pass if I were in that situation. If there is a Zeagle shop near you, then I'd go for it.
If you only dive once a week on vacation, the service costs might be more than rental costs would be. Therefore you'll never recoup the price of the regulator. But it's probably a better quality regulator than is available to rent in most places.