I updated to the latest (7.1.8?) and that fixed the inability to use 3d acceleration. But yes I've found they have a terrible release "process" that seems to not include testing. I tried switching to VMWare but
A) broadcom makes it difficult to download
B) since a recent kernel/driver update on my host, even a fresh Windows guest locks up in boot (can't get through install).
Might try going back to qemu. VMWare had the best performance by far, though, which was great for windows only 3d model software. When with 3d acceleration Virtualbox is so sluggish for me.