Evanix Viper - 1 - I like the finger groove-less grip of the Evanix. But also, appears to be somewhat short.
2 - Don't care for what "appears" to be a larger receiver group of the Evanix.
3 - Don't care for the LARGE barrel/muffler diameter of the Evanix.
4 - The Evanix safety lever appears to be a little more accessible than the Huben.
5 - I like what appears to be the Foster fitting is actually part of the gun.
GK 1 I don't have an Evanix, so all I can mention is about the Huben.
Like -
1 - The trigger is nice outta the box.
2 - The gun balance is nice (not overly nose heavy), easy to aim/hold on target during offhand shooting. Have light mitigator.
3 - The GK1 "looks" better balanced than the Evanix.
4 - Sort of a "like", mine came with a fill port plug and a mitigator adapter for no additional cost, (KRAZ Cool Guns).
Don't like -
1 - Don't care for the safety lever placement. The pressure gauge and the safety lever are too close, have to use two hands to manipulate the lever.
2 - The trigger guard is...well...!
3 - Don't care for the finger groove grip, also a bit short for me. Need to do some rework.
4 - I'm not normally a safety lever user...been a little difficult to remember to use it. Yes, one accident, no damage.
Expensive, but so far, no complaints. Would buy again, no hesitation.
Mike