Lobby, do yourself a favour and watch Close-Up. I am personally recommending it to you. Even if it doesn't instantly become a favourite for you as it did for me, it will no doubt be one of the most valuable film watching experiences you'll have had in a good while.
I think the love or non-love of Certified Copy comes down to a simple thing. It's all about whether you find the discussion interesting right from the start. I found that more tangential conversation at the start about copies extremely interesting, which then lead to some really interesting thoughts about what happens later in the film between these two characters. Once you're on board I think you're in it for the whole ride. But if for whatever reason you can't connect to the characters or the discussions they are having don't grab you, then the whole movie falls apart.
For me, Certified Copy was an intensely captivating film about two people exploring the very concept of a long-term relationship such as a long marriage. The questions that it raises are, to me, endlessly compelling. And I'm not talking about the surface level, "are they actually married or not?" sort of questions. I was much more interested in the idea, for example, of a marriage several years in being a different, or even lesser, form of the marriage at the start. That in a sense when they go out in public or when they try not to fight with each other by not expressing their true feelings, they are basically trying to create a copy, a forgery of a relationship that no longer exists, or at least doesn't in the same way. This opens up a whole other can of worms, which is to do with whether any two people can maintain a flowery relationship over such a long period, or if people just become comfortable with their situation and with the people around them.
It also helps that I found Binoche totally charming, and I thought both characters were great, well-developed, and fully drawn. Their conversations felt natural, but always interesting, and much like the "certified copies" they look at in the first half of the film, there is much more under the surface of their words than either of them would care to admit. It's through conversation and the little "game" they play that the layers of their characters are slowly peeled away, and I loved every minute of watching that take place.