Slovakia certainly deserves more BIGs, especially when you compare climbs in Slovakia to some other, flatter countries. One excellent climb with very good surface and lots of turns and some hairpins is Kviacianske Sedlo close to Zuberec and Habovka where cyclists stay during last Tatras meeting. This is also one of the most beautiful climbs I came across in Slovakia. The views are magnificent.
NW side of the climb starts in Podbiel at the elevation of 562m and takes 22.2km to get to 1076m which is 532m diiference.
S side of the climb starts in Liptovska Sielnica (which is close to Liptovsky Mikulas) at the elevation of 571m and takes 14km to get to the top finishing at 1076m which is 514m difference.
Data according to bikeroutetoaster.com. On my paper map the top is at 1110m.
This climb also fulfills two conditions I suggested for BIGs, at least 500m difference and/or 10km long.