Fate/Stay Night and Shingetsutan Tsukihime are two completely different anime series based off
two completely different video games produced by Type-Moon. Therefore, they must be compared.
Round 1: Teamwork
Shingetsutan Tsukihime:
Shiki Tohno is the textbook definition of a pussy. He gets bitched around by Arcueid, Akiha (his little sister), and pretty much everybody else in the show. He has a totally badass ability to cut stuff up without even trying, but he's just too much of a pussy to use it. Exactly how much of a pussy is he? I'd say he's somewhere in between Watanuki (from xxxHOLiC) and The Pussy (from Not Another Harem Anime). That's bad.
Fate/Stay Night:
Shiro is a sexist, but not in the sensible way. It's clear that Saber could kick Shiro's ass with both hands tied behind her back and a leg chopped off, but Shiro won't let her fight because she's a woman. I don't know what his problem is. Not only does he suck at fighting, but he has Sakura, a girl who already handles his cooking and cleaning. He doesn't need two.
Both couples suffer from shitty teamwork, but I'll give credit to Tsukihime for at least being somewhat believable. If I met a woman with mystical powers, I'd have no moral qualms about letting her mutilate people for me. In fact, I'd encourage it.
Advantage: Shingetsutan Tsukihime
Round 2: Art and Animation
Fate/Stay Night: Commendable artwork and animation.
Shingetsutan Tsukihime: This show has the widest gap between art and animation quality I've ever seen. I don't know if the animation team was underfunded or just plain lazy, but the effort was obviously lacking. Just watch the beginning of episode 8 and you'll understand. Start with this ferris wheel:
It's hard to illustrate my point with still images, but trust me, when you see this ferris wheel animated, it's rotating in discrete movements and looks really stupid. After the ferris wheel incident, the scene shifts to the school cafeteria where you're reminded that the animators were too lazy to draw people in the act of speaking. In the following scene, somebody is talking, but who?
Can't figure it out? Maybe this next scene will help. It narrows the possibilities down to, I don't know, how about everybody in the entire cafeteria? It's pretty hard to tell when nobody's moving.
Who's talking? Is it Tohno?
Nah, it couldn't be Tohno. How about Ciel?
Wrong again. All she did was hold that exact pose as the camera slowly zoomed in on her from 2:41 to 2:51.
I'd say that the artwork in Tsukihime is slightly better than the art in Fate/Stay Night, but assuming convex preferences, it's not enough to give Tsukihime the win.
Advantage: Fate/Stay Night
Round 3: Fanart
You can find awesome fanart for both series here. It's a tough call, but I'll give the edge to Fate/Stay Night, simply because there are more characters to work with.
Advantage: Fate/Stay Night
Round 4: Plot
Fate/Stay Night: If you got the feeling that the anime failed to tie up a few loose ends, you don't know how right you are. After checking out a lot of the fanart, I can assure you that there are several issues from the game that were never fully explained in the anime, and that's not even the worst part. Apparently in the game, there's his evil version of Sakura who looks like she'd go around maiming orphans and cripples for fun. What the hell were the producers were thinking when they left her out? "Here's a brilliant idea: Let's prevent this show from living up to it's potential by leaving out Evil Sakura". Idiots.
Shingetsutan Tsukihime: A solid plot. There were a few things that could've been explained in greater detail, but for the most part, I can't complain.
Advantage: Shingetsutan Tsukihime
Round 5: Voice Acting
Fate/Stay Night: Great voice acting. (sub)
Shingetsutan Tsukihime: Good voice acting interspersed with a handful of brilliant lines. (dub)
If you're familiar with my opinion on Dubs vs Subs, you know that with few exceptions, I prefer a coherent dub to its sub.
Advantage: Shingetsutan Tsukihime
Winner: Shingetsutan Tsukihime