I think Claymore is best for monero's hashrate
Against a tweaked XMR-stak config file, not really.
I agree, but have you checked out the SRBMiner-CN? Looks very promising.
Doktor made an awesome job.
I haven't tried latest SGminer, but I think it is still the king. XMRig has also better hashrate than XMR-STAK 2.x, the old AMD version was a way better. Claymore is probably the worst option out of these, but it has no fee now and it is very user friendly, only power consumption was high, not sure with these latest versions, haven't try it for like half a year.