I am running cluster of two 1470 appliances used by 70 users, 5 SS VPNs, few remote access users on a dual ISP connection with total 100 Mbps capacity. Not too much I think. Build is also 437.
Some days it will work fine, no issues. But on most of the days SFWD will crash every now and then. It is immediately restarted by a watchdog service and there is no failover in the cluster. In fact the only visible effect is that all SS VPNs are restarted (currently open user connections are dropped). I have no other custom settings on the device other than the RSS memory increased to 300MB. R77.20.75 build 239 was the last one that had stable SFWD process that never crashed.
SecureXL does not work also for me. When I enabled it device restarts in few minutes. TAC was able to fix that and provide me with custom build but I had to replace it with 437 because of the CVE security fixes. I hope they will include this fix in the main branch.
HTTPS Inspection generally works here but I have disabled it because of the SNI problem that seems to be properly fixed only in R80.10 so far. Check this thread:
I hope stability will be improved even more but as we discussed in another thread current Gaia embedded design is not very good (everything is handled by a single process). I am assuming this and other things will change in R80.20 if it is still planned release for SMB.