I did read it last year when I just started on Proust, and it wasn't what I had expected. Turns out de Botton was writing a farcical "self-help" book by applying the lessons as illustrated in the Proustian epic. It isn't a literary discussion of Proust of course, and probably will make a lot more sense after I've finished reading Proust - but it was funny.
I was going through my reading journal this evening, and I came across something I copied from How Proust Can Change Your Life. Alain de Botton is quoting Marcel Proust's brother, Robert:
"The sad thing is that people have to be very ill or have broken a leg in order to have the opportunity to read In Search of Lost Time."
Somehow that made me laugh, and it made an impression enough for me to copy it down.