Well, if you do NOT already have at least a PVS-14 for your head, that needs to come first. Don’t even consider anything weapon-mounted until you have that covered. You can use a rifle very effectively out to 100+ yards with a 14 on your head. You can also stick a PVS-14 with 3x USGI magnifier behind any NV-compatible RDS (Aimpoint, EOTech, etc) and that will get you out to 200+ yards. Between IR laser/illuminator and a QD weapon mount a PVS-14 becomes the most versatile NOD available, and they’re relatively inexpensive.
Once you have that covered, then a clip-on begins to make sense. On the somewhat lower end, the Armasight CO is solid. Moving up in the world, there has been a spate of PVS-27 and PVS-30 units flood the market recently. These have been scored at insanely low prices and are best-in-class performers. With a unit like those and good illumination you can reach targets out to 500+ yards on the darkest nights.