I almost exclusively use reflex sights. They're cheap, the reticles are bright enough to see in sunlight (you don't have to play the lottery on getting one that's bright enough like the eotech replicas) They're often cheaper than the eotechs.
I find a circle reticle much more useful in airsoft than a simple dot sight. Simply because airsoft guns shoot in a cone, rather than a line. With a circle that's probably zeroed, you just fill the whole thing with target and shoot.
A dot sight imo is too precise for airsoft. You put the dot on something and your rounds will be out and around the dot. A reticle gives you a visual reference of your cone of fire. When you start to understand the groupings your gun shoots at various ranges, you can immediately figure out how tight your cone will be in relation to what you see in your sight.
I futz with V2s, V3s and V6s. I could be wrong... but probably, most likely not, as far as I know.