The plot of this series, is to be honest, pretty horrible. It's extremely linear, it's pretty boring, and there isn't really very much in terms of plot twists or suspense. And what little they had, which was more towards the end of the series, was executed rather badly with bad pacing and ass pulls galore. In mitigation, this was likely caused by the developers buckling under the twin strains of running out of budget and having to merge the three different scenarios from the visual novel together. However, it's still bad.
The saving grace of the series lies, frankly, outside. The backstory, the concepts dealt with, the underlying metaplot, the thoughts provoked - fantastic is an understatement. Sadly, in order to be able to enjoy this, reading the Visual Novel is a must. The anime simply did not have enough time to cram in all of the information, resulting in a jumbled mess.
Another strong point of this series lay in the characters. Every single character positively exudes personality - from just hearing one line, you can basically pinpoint which character it is from. However, this is coming after I've read the Visual Novel, and also all the associated mythologies of the characters. If just watching the anime itself with no prior knowledge, the Servants can be a bit... one-sided. The thing you have to remember is that you're *supposed* to know the characters beforehand, and that the development present is an expansion on preexisting perceptions of these characters.
However, there's one exception to the strong characterization - the main character. Given that this was an adaptation from an eroge (hardly a medium known for strong main characters), you wouldn't really expect much of Shirou. However, Shirou does not possess the usual blank self-insert personality typical of eroge protagonists. Quite the opposite, in fact. He has an extremely strong personality, and it's grating to the extreme. There are plenty of times where you wish you could just slap the damn child out of him, and unfortunately, the scenario where that *does* happen was not animated.
Animation quality was extremely well done, with a clean art style that's extremely refreshing, and well animated fight sequences. Sadly, this tended to suffer near the end of the series as the animators ran out of budget.
Sound is a non-sequitter. Nothing really stands out, nothing's really bad.
In conclusion, Fate/Stay Night has a marvelous backstory, beautiful characters, and a mediocre plot. In trying to shake things up from the Visual Novel, the director appears to have set too high a bar for himself to attain, running beyond the limits of himself and the budget. While the animated medium makes for a much better flow of story than the Visual Novel, which had shaking pacing at best, in the end it fell prey to the pitfall of no money.
