Have booked the apartment and the transport from Odessa airport to Nikolaev and back. In short, only I can say that the service was PERFECT!
The apartment looks same as on the photographs, published on this site; it's maybe small, but it is cozy. All installed equipment works fine, but don't expect that you'll have many programs on sat-TV. I asked for Internet connection and laptop for rent and this part was perfect too. The internet connection is fast, but I recommend to bring your own laptop as some programs have Russian menus, which are difficult to change to English. However, I changed Skype program to English.
One advice: order VIP service on airport when departing Odessa; next time I'll for sure order it. Dmitry, thank you so much, I enjoyed to stay in Nikolaev. In addition, I'll ask you for help me in everything else as I see that you're well organized.