I see that Kemper use same technology as software with IR-files
Where do you see this? 
Kemper IR are dynamic, and computer IR are static. Big difference. Maybe he just means they emulate cabinet / mic EQ, not keeping in mind the dynamic and static difference?
I haven't tested it side to side, but I used to play through my PC at home before I got the Kemper daily. I never used the IR's in Amplitube 3 (or any amp VST for that matter) and always used 3rd party IR's.
I haven't looked into using the IR's I used with VST's for the Kemper because it doesn't need it in my opinion. So yeah, I'd say the Kemper IR's are better.
I have Cab Maker installed that import IR files to the Kemper, so I thought that they use same technology to emulate cabs, but I might be wrong.
It is not the same. The IR you are converting into a cab file is a single snapshot of an EQ (static) When you create a profile on the Kemper using a real cab, it takes multiple snapshots of the EQ (Dynamic).
