I have only read Swann's Way, the first of the Proust sequence, and was actually pleasantly surprised by how easy to read it was. I took it with me when I was having to do a weekly long train journey, to make myself get into it after years of putting it off.
I'm so glad I did as I absolutely loved it, and many passages of it were very beautiful and have stayed with me since, and even the famous madeleines description I found lovely in context, despite having heard it boringly often previously.
I have the others put by for when I have more time to read.
Also would urge people to give Anna Karenina a good go, it was a real page turner by midway through, and I have never read anything awful written by a Russian.
Cloud Atlas, several attempts, could not get to grips with it, likewise Catch-22, also Birdsong though I know some people love it.
Thomas Hardy, nope, read Jude but otherwise too many words and so little reward.