I really like this card, but before I get too much into it I have to say the whole Turbo switch thing does seem a bit pointless. Honestly, why wouldn't you want to run your card at full tilt all the time? - And considering you have to shut down to switch between the clocks, it makes it a bit of a pain.
I'm also not sure about your setup, but if this was in my main PC, getting to the back of the card to switch from normal to turbo would be even more of a pain. In turbo mode the card didn't hiccup once, it ran like an absolute dream which again kind of puzzles me as to why one would opt for "normal" mode.
The thing is, though, the card ultimately performs great. It runs cooler than the stock HD 4870, manages to look a bit better, performs slightly better, costs only slightly more and generally speaking is just pretty kick ass.
If you find yourself wanting something a bit different while also running a little bit faster, the Palit HD 4870 Sonic is a great option. As far as HD 4870s go, there isn't a whole lot more you could ask for. Throw in the fact that Palit have also added Display Port and the card is pretty feature packed.