I found Jeri Ryan sexy in her numerous catsuit incarnations, but I didn't find it appropriate for her new station on board. She's a technical member of the Voyager crew. She should be in an appropriate uniform. Now, there are some uniform variations that have been tolerated before. We have T'Pol and Deanna Troi who have had custom variations. Personally, I think T'Pol had some nice ones. Some are too "catsuit" like, while others are more like work jumpsuits. I'd have liked to have seen 7of9 in one of those for her duty uniform.
But if she had to be in a catsuit, I'd say it would be the silver one. It's the one that looks most Borg-like. One could also say that after the removal of all the Borg implants and having been a Borg for so many years from a young age, she needed a special "sheath" over her skin to help condition it and prevent infection. Although... we see no real case for that when she has been shown without clothes on in some episodes, and her skin is blemish free.
We also never get an explanation as to why she has just two external Borg implants left--the one over her left eye and left hand. Maybe they're benign enough and actually provide a benefit, that it was decided to leave them in. Certainly the internal nano-probes are still there, as well as the tubule stingers.