It's pretty solid, I'm using the Linnmon Blue-Black, 59" x 29.5" with a Vivo manual height adjust workstation frame and it's superb.
The Vivo (that I highly recommend, build quality and customer service) doesn't ship with a table top and Vivo doesn't offer one, so it's about sourcing your own. I wanted something to try that wasn't expensive in case this whole desk was a bust, and also something that was an interesting design, so I searched around some DIY sites and saw a few folks using Ikea desktops. I also found (per Amazon) that a lot of the cheaper desk tops (still talking $80-90) were damaged in shipping (not Ikea, I'd assume they package shipments better) so I took advantage of our local Ikea and just picked one up in person - also have me an opportunity to look at all of them, confirm my choice.
So the Blue-Black has a very flat (blue-ish-gray) top - the outer edge is a light birch color, very cool - anyway, that could/can/will get scratched unless you use a little caution, like items that have rubber feet, or are just soft, no sharp edges. Some of the other finishes are more glossy, I'd figure they're probably a little more durable. I can't imagine this sagging, but my frame has this huge cross bar that goes under it longways, so it's not going anywhere
The middle area is less dense, the outer 6-8" (where the pilot holes are for Ikea legs) are very solid.
The best part is it's almost a "disposable" cost at $39, and I just looked at the Black-Brown is only $29. When this gets beat up, I may just get another Ikea top (though I found a nice, real wood top, with a thick poly-u type finish, way heavier, 5X the cost, guess I'll see when the time comes ...)