Although this is a truly magnificent film with a great script; impeccable acting from all four leads (Kristin Scott Thomas, Robert Redford, Sam Neill and a 13-year-old Scarlet Johannsen), admirable self-direction from Redford and cinematography that captures the very essence of the Montana grasslands, it will most definitely not be for everyone.
Let's begin with the pacing. The film is 16 minutes off being three hours long. If you're mad about horses, love pictures of landscapes, get lost in romantic movies or could watch Redford/Thomas all day, this is not a problem - time will fly and you should buy this film immediately. If, however, you're more of the action movie type, then the subtleties and nuances of the film will pass you by and the time will drag. A fair test might be “The Remains of the Day”; if you liked that, you'll probably also like this; if you felt nothing ever actually happened in that film, save yourself a rental fee.
The one other sticking point might be for those who read and loved Nicholas Evans' novel on which the film is loosely based: emphasis on the 'loosely' here. Although the film mirrors the book to start with ¬- the horrific accident that maims both horse and girl - the development of the two plot lines is given a different emphasis in the film. Hollywood have also done to the ending what they so often do ¬- as per “Captain Correlli's Mandolin” ¬- and changed it, not really for the better, though doubtless that was the intent. However, this epic is so good that, not only are you prepared to forgive this, but not knowing what is going to happen in the end actually adds a piquancy to the romantic angst that otherwise might be lacking.