I would stretch the budget.
This is one of the tool places I don't skimp. Longevity and torque require a good impact.
I really like my Snap-on MG 725, but they are proud of them.
I have a Sioux Tools impact in 3/8" and based on it's performance I'd by it's
1/2" Big Brother in a heartbeat if I needed a new one.
The
IR 231 has been around forever, and is probably as low as I would skimp for an impact, but it's both heavier and weaker then the other two I linked.
Look at it this way, if a ratchet doesn't work, you're going to an impact, but if your impact doesn't work you're probably going to the torch. You really want your impact to work.