Should I buy Arma III ?

Im played alone for first 2-3 mouths its nice but after thet i feel monotony... I do not playing mods not tell you how the case looks

I've played Dayz both alone and in group.
In group is more random, joking on TS3, handcuff people and make them sing, etc...
Alone is more immersive, you have to watch your back, if you find a group of people you should play stealth, avoid or ambush them, it's more hardcore.
is funny anyway, but imho it's really different, if arma3 mod's are similar you should have fun both alone or in group
(a microphone is really recommended)

It's fun with friends. There's loads of mods. But I don't play DayZ or any like that.

DayZ mod is for Arma 2, not Arma 3.

Arma 3 is really meh cause there is literally no content in it. While there are a few modders making some good stuff they are at least 1-2 years from releasing something substantial.

No