Not expecting much of a price hike, probably more in the tens of pounds if if not the same. This is the commercial version first iteration, so no, its not a dev kit.
As to best - ooooooooooh, you're going to get a lot of opinion there. The Vive looks like its best for standing up and walking around experiences, the rift for seated. Mind you, im pretty sure we havent seen everything yet with palmer dropping serious hints theres an input device coming for the rift, so bit of this and a bit of that. theres also the hololens, which is AR and eye wateringly expensive (im thinking around the grand level, but thats based on nothing) so theres a little bit for everyone really. Depends what youre into.
They are saying they'll be releasing a lot of info including unannounced games, in the next couple of weeks and of course theres E3. Im looking forward to Game of Thrones announcement! Theoretically!