They're adequate, and have tritium in the front. They aren't what I'd want to rely on forever though.
As said above, get the gun first. Secondly, you can't go wrong with a Primary Arms mini red dot, those things are built like a tank. The new ones have something like 50,000 hours of battery life as well.
My priority list would be,
Gun
10 mags and enough ammo to fill them twice, so 600rds.
Optic
As much ammo as you can afford, or a loading set up, primers, powder, projectiles, and a tumbler. You'll already have brass, and you can still pick up bras at the range for free in 5.56/.223, so you should never buy new brass. You can get about 7-10 loads on AR brass depending on the headstamp, and looking at the condition of the brass from the Tavor it looks to be easy on it, so I'd say you'd be real close.
After that, buy a combat proven optic.
Then, more mags and ammo, or components.