I too expect Sony to tire of the PRS and move along. I'm hoping that by then there will be significantly better options around and in the meantime I'm not buying secure ebooks. In any format
So far that has not been much of a problem, Fictionwise and Baen have good selections, reasonable prices and Calibre does most of the conversion work for me.
To be honest, the formatting thing doesn't matter to me. I've spent way more time removing formatting than trying to get it to match anything in particular because mostly I read novels. Which means I want no margins, small fonts and if I could remove all page breaks that would suit me just fine. The only thing so far is that I'm not enough of a Python programmer to get feeds working for the most part (ie, they either work immediately or I never get them to go regardless of how long I spend).
So what I'm looking for in the future is probably better software (ie, maturity) and a two-page device rather than any radical advance in hardware. And, of course, the demise of DRM.