I haven't been to any. I have no single favourite, the Turkic republics have preferencial place in my heart, i can relate to them (if I had to choose, Uzbekistan for its important historic cities, Kirgizistan for its nature, Azerbaijan for my affinity to their language). But Georgia and Armenia also looks awesome, have the two weak spots I really like, rich historical legacy from a (for me) unusual culture + huge mountains. But the old towns in the 3 Baltic states look really nice too, similar to the Central European towns, so they have a familiar atmosphere for me.
I believe there's a transparency index. "Transparency" is the actual thing measured. It assumes that only state secrets that are reasonably required for national security or legitimate justice issues are necessary. Other lack of transparency it goes against the transparency rating for government operations.