Their CCR-series is very much bang per buck if L4-filtering is enough, which should be enough in today's world of end-to-end encrypted communications.
The CRS3xx-series as stated has become much saner with changes to bridging and with most features implemented are also worth the cost.
The upside with affordable devices and the licensing model they have, make it possible to keep cold spares available in case of disaster.
It does however make sense to study the management interfaces and disable all but SSH and HTTPS in order to minimize attack surface.