In my experience XFS is rock solid. We use it almost everywhere at work. I've never had an issue with hard reboots with it. Only recently started playing with btrfs, so can't speak to it's reliability from personal experience.
Some reading if you're not familiar with sysrq: https://en.wikipedia.org/wiki/Magic_SysRq_key Depending on your distro you might have to enable it, I believe ubuntu (for some dumb reason) ships with emergency sync as the only command available.
Enabling it should amount to adding: kernel.sysrq=1 to /etc/sysctl.conf on older machines or editing /etc/sysctl.d/10-magic-sysrq.conf on newer ones.
also if you are running out of ram that often you might want to consider a swap partition. Or if you have one already try setting a more aggressive swapiness value.