I find that their tech support is excellent. And as a reseller, my relationship with my point of contact is also strong. WatchGuard does a good job of maintaining that.
WatchGuard Data Loss Prevention issues warnings and configures compliance emails, effectively blocks data per policies but captures insufficient traffic. Integration is reliable, yet high RAM use and VLAN limits cause issues. Pricing is high. Technical support is excellent though data loss prevention support needs improvement. Reseller relationships are strong, and service is highly regarded.