No one can answer this for you really.
For me, the difference between 144hz and 75hz is night and day but I play fast FPS mainly (though I can't get by in desktop with 60hz now). 1440p is far less important to me than latency and I'd opt for a 144hz 24" 1080p over 1440p60 on a 27".
If you are able to visit a place that will demo 144hz for you, or have a friend with a high refresh rate panel, this is the best way to feel the difference. You get an immediacy, and a feeling of being more in touch when playing on a high hz panel, such that I find it far easier to "flow" on one. If you play slower games and look at the scenery more then the difference may not matter to you.
For the same reason I just accept tearing and use no adaptive sync, as they all increase latency. The majority of people are probably happier removing tearing and coping with the latency overhead imposed.
I don't have any experience with adaptive Vsync and so cannot compare it with Gsync, Gsync works as intended though, removing tearing and not displaying the same hitching that Vsync does; whether that is worth the premium to you is personal.
I watch this bloke for netcode analysis, but this seems to be quite decent for adaptive sync also -
Battle(non)sense - FreeSync vs. G-Sync Delay Analysis