I used Soviet Wonders for two packages - 1 was for a shooting range, where you got to fire a few guns - I really enjoyed it, Christina organised transport to range, the instructors were really helpful too.
The second package was a day tour to Chernobyl exclusion zone. Our guide was a woman called Lisa (I think that was her name, blonde hair), she told us a lot of really informative things about the area, she was very pleasant, helpful, a really nice person! The tour leaves early in the morning, you stop in a garage on the way, to get some snacks, you also get free lunch in Chernobyl power plant canteen - although I can't compare with other tours, I'm glad I done it with Soviet, as the group wasn't too big. The tour minibus is comfortable, with good Wi-Fi. I wholly recommend doing the tour through soviet wonders, if you get Lisa your in for a treat!