Depends really, they've both gotten better but their budget computers aren't all too bad.
Take these two models for example at the same price:
HP:
https://www.walmart.com/ip/HP-Pavil...Horizon-Blue-Windows-10-15-cw1064wm/716241760
Acer:
https://www.walmart.com/ip/Acer-Asp...Me-SSD-Windows-10-Home-A514-52-78MD/471842473
P.S I know this is walmart but that's besides the point.
If you look at their specs you can see HP has a brand new CPU model in it but a slower SATA M.2 SSD with a 1TB HDD combo. Now this isn't bad but it thus requires you to pay for different components since that SATA ssd will die relatively quickly.
If you look at the Acer, it has an older CPU model but a much better storage solution. A PCIe NVMe that's much larger, faster, and will most likely last longer. Perfect for someone who wants quick speeds and not all the storage in the world. But if you want to upgrade you'll have to upgrade that NVMe.
So you see the build quality has gotten close to standards a normal user would find satisfactory, but there are caveats to either option. It all comes down to what features you need and at what price.