I have one, its fine (a search here would have revealed this, I've posted about it several times in other threads - maybe Lekky should sticky a post about it).
Its fine in the phone, it doesn't need to read data faster than the read speed of the card whilst in the phone for things like apps or music, so other than making large transfers to the card (usually only happens initially when loading your music, for most people anyways) you shouldn't notice a huge difference/any difference at all for the majority of use. Gallery apps tend to be a little slower loading, I think because they refresh themselves each time they are loaded to look for new content.
There are no cheap suppliers. Still exclusive to Sandisk for the time being (I believe Play and similar sites will have sometime soonish, but keeps getting delayed as Sandisk aren't making enough to keep up with their own orders). So if you see them being sold more cheaply, like for example the numerous ones on Ebay, you are almost certainly looking at fakes. If you live outside the US/UK and have no access to Sandisk's online stores do what I did - use Shipito to get it from the US to wherever you are.
