Yes, it's a well made PSU, as you've claimed, it's an old unit, but that doesn't imply that's bad.
Seasonic makes great PSU, that one is still very much reliable if you do not have the means to get a newer model.
But, it's good for a certain scenario, as it's, if i'm not wrong, only 520 or 620W, so your PC parts shouldn't go beyond that.
If you're aware of how much wattage your PC will need, you can't go wrong with that PSU.