I had levered down my expectations a few notches based on some negative reviews I'd seen*, but honestly, I don't think I needed to. It's a romantic comedy, so yeah, you know the general outline of what's going to happen from the get-go. And there were a handful of flawed moments where it was a bit awkward or predictable or clumsy. And of course it's all sappy -- see "rom-com", above, duh. But I laughed out loud a whole lot and generally just enjoyed the heck out of it.
There's a lot of good physical comedy. Simon Pegg is really good at falling down. I also actually noticed the direction (by David Schwimmer) some, and I liked it. There were a number of shots where the scene lingered a little longer, or focused a little differently than you would expect for the "standard" Hollywood version of the scene, and I really appreciated the little added embellishment. It was kind of like, I dunno, a hint of lime zest in the chocolate cake: unexpected, but when done right, it really adds a lot. Plus, Dylan Moran is brilliant, and the rest of the supporting cast were all great -- even the kid!
*This is my theory of movie-watching: try to figure out about how good you'll think the movie actually is, then go into it expecting it to be two notches worse. Then you'll very rarely be disappointed, and most of the time you'll be pleasantly surprised because it exceeded your expectations. Either way, you win.