went on a similar holiday with TS back in 2005, although it was nothing like that price, even for 2 of us and with a few days in Toronto included. It really was one of those (cliche alert!!) holidays of a lifetime. You definitely need the warmest clothes and the best boots to deal with the ice that you can find. I seem to remember that the temperature during the day was about -20C and there was a 20mph + wind, which equates to feeling a bit on the parky side. Inside the tundra buggies is toasty as there is a big heater and they served soup and rolls during the day. What's funny is, the first time you see a PB, it'll be a fair distance away and everyone jostles to take a "maximum zoom" photo. Of course, by the time you've been out on the ice for 2 days, there could be a troupe of PBs juggling seals and you'll be blase and say "oh yes very nice". The plane that took us from Winnipeg to Churchill was a real throwback but a great experience. All I can say is, if you want to go, and the cost isn't an issue, then go for it, you won't regret it.
Anything else I can try to answer?