Honestly they're probably the same LG panel. If you're getting them for the same price, go for the official LG offering. The crossover is going to be the same panel as the LG, but its probably a panel that had a qwirk or two which is why its a crossover. Your more likely to have dead pixels and backlight bleed with a crossover vs an LG. My vote is LG especially because you said about the same price.
The Crossover 290HD is a few dollars cheaper so it might be worth looking at. Personally, I would go with a 1440p monitor. The IPS Crossover (and other Korean off brands) are really solid. Same number of pixels horizontal as the 290W, but with more pixels vertically. A sound choice imo regardless of how you go. The 290M, the 290HD, the 29UM58-P, or the 1440p ones are all good choices.
I have a 32" 4k monitor. I honestly wouldn't want a much higher ppi. 28" is simply too high to be comfortably usable imo. I am loving 32" though. If you can stretch your budget (maybe save up some more), the new 31" IPS 4k R4K310C is what I would be going for.LG IPS panels are gorgeous and 32"ish 4k is a real treat (assuming your vision is pretty good).