Well well well, this first episode puts me in good hopes for the adaptation; it really let us understand Shirou, how he thinks and where he comes from and really lets you get a grip on his character. Comparatively speaking, this felt a lot less padded out than Rin's episode, though that might be for the lack of time spent with people expositing stuff they already know at each other. The slice of life bent felt natural; I mean, given it's about to be merrily tossed sideways by the Holy Grail War, it's important to show how things were. It grounds everyone, if you get my meaning; it sets all the starting points and gives us a chance to relate.
The problem I always had trying to wade through the VN was that it crawled along at the pace of a snail in wet cement and felt like it stopped to explain every little thing... usually, two or three times over (I remember Nasu having a particularly irritating habit of explaining a thing, then finding three or four other ways to explain that exact same thing with different wording, to the point you have an entire paragraph explaining a single detail unnecessarily. The... dry... translation didn't exactly help). The adaptation though happily dances right over those; the details are still there but it doesn't break the pacing's legs to ensure you stared at them enough. This also applied to understanding Shirou; this episode though fixed that admirably... though to be fair, given he was the viewpoint character he was always a little hampered in that regard in the VN (because you can't see him).
The fight scenes felt a lot better than the Prologue's. I think I've finally put my finger on why too; in particular, when Gae Bolg happens and the camera just flies all over the place, I found it really, really disorientating. The prologue fight had a few instances of that, and it made it hard for me to follow what was happening. Apart from the Gae Bolg moment though it didn't really happen here; it left the fights feeling a lot cleaner and easier to read. Compared to F/Z, I think they also did a lot better job of showing just how inhuman the Servants are; every time they attack each other it's like they're firing themselves from cannons.
Have to agree that, compared to F/Z's OP/EDs, UBW's felt a little underwhelming. Maybe they'll grow on me, I don't know.
(as an aside, comparing this to the DEEN anime is almost pure, distilled schadenfreude)