Having driven both I must say while the 2121 (the USSR Niva) has great nostagic appeal, the Chevy Niva (https://en.wikipedia.org/wiki/Chevrolet_Niva) is quite a bit more comfortable. Still the same problems with reliability, since it's just a new body on old everything else.

Edit: all in all, I prefer a diesel Hilux and/or suitably old Landcruiser for the offroad duties. Going anywhere on a highway is a pain in either Niva.