It depends what you want really, the AW2725DF is more of an esports panel if you ask me, it's very expensive for a 1440P 16:9 that you wont likely be able to really take advantage of for long enough that something else will have come along to make it look old by then. The AW3423DWF is a better alrounder I think and if you are used to 16:9 will offer you a view you may never have seen before, not just a higher resolution but a different experience, weather or not you think it's 'better' is a matter of opinion of course, I do.
These monitors are not really in competition, they shouldn't both be on your short list, they are different displays aimed at people with different sets of requirements, one is 21:9 and one is 16:9 and deciding the aspect ratio like that, should be the first thing you do and then narrow down from there, so figure that out to narrow the field for yourself. For me, it doesn't matter how good the latest generation of OLED's are, they are not 21:9 so not in consideration for me as I find 21:9 makes more of a different to me than anything else they can offer beyond what I have.