If you are reminded of horrible aspects of yourself in the portrayal of the protagonist you may, like me, find this film personally devastating. But I think in the end the films concepts are stronger than the film itself.
Around 3 and a half stars, or a little below it.
The film does feature a promising script from Zoe Kazan.
Perhaps if it had better directors, who were open to exploring Dano's character/giving Dano's character more heft (besides the critique within the central conceit) the film would hit better (or perhaps this is my controlling 'we have to have a full grasp of the world' side coming out.) I think, the way it is, the conceptual critique of Dano's character is more alive than the character itself, despite Dano's perfectly fine efforts on a scene by scene basis.
For example, we are given a nuanced (albeit occasionally spell-it-out-ish) critique of Dano's controlling emotionally stunted behaviour, but we are only given very vague inklings of the reasons/roots of said behaviour, simply from the background setup we are given (it was until the day after I saw the film that I could think of some reason why.)
But while one might guess possible reasons, (possible hints hidden in the screenplay? Dano's mother molding her persona to suit her partner and ex husbands outlook for example) to me there is nothing here to suggest the directors are thought about this area. We really aren't given an inkling by the directors what drives him and these flaws which the film highlights/condemns
(I am not saying it has to go into totally obvious drawing of character, but some kind of intimation would have added nuance to proceedings arguably, would have given Banderas/Bening a genuine reason for being there, and they had the opportunity to slip it in.
Saying that, there is a moment [a slight moment] where the script brings up parental influence, when Dano's character is thrown an odd and overtly obsessive parent related question from a fan [with regard to the central character of his 1st book] and it is presented to us as a silly thing to be concerned about. Maybe the makers of the film had genuinely thought about including that parental angle I mentioned above with their own protagonist, but thought it unnecessary, or pat, or too focused on the past/lacking focus on the now, or in some way negating a personal responsibility of the protagonist.)
Anyway, while the cast do well with what they are given, and scriptwriter Kazan should be commended for doing well in a difficult [literally manufactured] role, I think it is only Chris Messina's brother that feels someway rounded/human - lunkheaded, flawed but convincingly wise through experience (said roundedness feels more down to the adequate marriage of script and performance than a directors input, although yeah thats just a first impression, I could be wrong.) The hippie parental figures are superfluous in the films current incarnation (sorry the contolling part of me is coming out again. Explaining/controlling the world.)
Plus the ending is horrible (I presume unintentionally. It may be the case that the ending is intentionally provocative in its patness/horribleness, but to be honest having seen little miss sunshine I am not willing to give the directors that much credit.)
While not inadequately directed (the film has significant merits in its fluidity and visual execution) I think a more thoughtful director/s might have mined the material better, and perhaps even created a better film.
Whats there is not terrible though, and overall, whether intended by the makers or not, this trip to the cinema certainly provoked alot of uncomfortable feelings and reflection for me. Which I suppose I should say is a good thing.