I have two dbal i2. One in red and one in green. I use them with the eagle tac or luna ir.
Using the laser during the day mostly...get green. To save money get red. just using the visible laser with NV get red and save. I would get the DBAl i2 when its on sale, around 840 in red. Green is easier to see and brighter...
I tried two Dbal D2 on the shotgun and they both broke (couldn't handle the recoil), but they might be ok for AR .223. They are the perfect setup.
The uses of the visible laser for NV. If you have a dedicated NV, pvs 14 or Day scope and it suddenly fails or can't use it during the day, To check your scope or red dot see if its still on, Easier to sight visible laser during the day. Sight in visible laser then get ir laser close to visible laser or red dot or cross hairs and check. To use as a pointer so your hunting buddy can take the shot.
The ir only version can save you some money.