If you want a full FW solution that can actually FW+NAT at 10G bidirectional without breaking a sweat then something like the FortiGate 90G is the cheapest thing I've found that performs really well across the board. Great QoS, great latency, amazing throughput performance (does well with even small packet sizes in a single stream), easy enough to use UI (once you get oriented), low power. If you want to enable all of the NGFW stuff (e.g. AV and IPS) then it'll dip below line rate though.
If you just want something that NATs/connection direction oriented filtering like a "normal" home router then something like the MikroTik CCR2004 can get you better than the performance they got on the VP2440 + give you 12 ports of 10G SFP+ to work with. If you were planning to do "fancy" FWing/functionality beyond a normal home NAT FW (with decent managed switching built in) then the feature set will be a bit limiting, of course.