Ran a FreeBSD colocated server for about a decade that went through generations of hardware. I really want to like the OS, except it's most touted feature, the network stack, was consistently unreliable for me using Intel NICs on Supermicro servers. They would go offline usually after some load due to mbuf resource exhaustion. I never got to the bottom of it even though I posted to the bugs database and would diligen…
Myself has been through generational hardware, and had had zero issues with any apart from when the raid card failed.
Network has been solid. ZFS has just worked. Not sure what your issues were however colocating since FreeBSD 8, and now colocating 16-CURRENT on my the server. FreeBSD has been rock stable in my books.
2x Dell R630 and 1x Cisco U220 M5
doublerabbit@cookie:~ $ uname -a && uptime
FreeBSD cookie.server 12.2-BETA1 FreeBSD 12.2-BETA1 r365618 GENERIC amd64
10:39PM up 1752 days, 1:31, 1 user, load averages: 0.64, 1.30, 1.31