Normally, this wouldn't be that a vastly important issue, but Fallout 3 is anything but a 'normal' piece of software. In a game that possesses such a minute level of detail, seeing every single edge shimmer with jagginess adversely impacts the most important part of the game: the 'reality' of the world that's being created. This is emphasised still further by the frequent changes in the frame-rate, and in the most curious of places.
The PS3 game handles the outside environments at 30fps with just the odd pause, but the action is frequently punctuated by a judder that sometimes makes you think your character has been crippled when it hasn't. When it really hits home (for example, in the enclosed environments of the Super-Duper Mart or the Rivet City marketplace), the frame-rate can hit rock-bottom at 15fps. The fact that the rate fluctuates so much - between 15fps, 20fps and 30fps in quick succession in some cases - gives the PS3 code a rough look, but equally as importantly, the video feedback to the movements on your controller is therefore equally variable. In the heat of battle, lining up a specific shot outside of the VATS system (hard enough already without keyboard and mouse) is even more difficult due to the jerky visuals.
Contrast issues aside, the Xbox 360 version of the game is basically a nicer place to be. There's still the occasional rough edge, but most of the image is filtered with 4x multi-sampling anti-aliasing - the same kind of ultra-fine smoothing as seen in Race Driver: GRID and Project Gotham Racing 4. The Xbox 360 physically can't do better than this, and while it's selective and not quite as good as the complete anti-aliasing coverage seen in the PC game, it's very, very close and plays an instrumental role in making Fallout 3's environments seem more believably realistic. Image integrity like this is a crucial part of the game, and the PS3 version loses something without it.
Head through the blue words for a startlingly large gallery of 720p gameplay comparison shots on all three systems, and enjoy the full cross-platform MIGHT of Eurogamer screenshot viewer 2.0.
Part of the Xbox 360 version's frame-rate advantage is down to the way it handles v-sync compared to the PS3 game. For the most part, the 360 game is locked at 30fps, but when the engine is struggling, it'll turn off the v-lock to maintain refresh rate. PS3 on the other hand remains v-locked come what may.
In a slow-moving game with relatively static lighting and not so much fast-moving left-to-right movement, screen-tear is a lot more difficult to pick up compared to your average action game, so the decision to lose v-lock in challenging scenes is most likely the right one. Unavoidably, there are some scenes where it looks terrible (for example, battling the Super Mutant Brute in the Project Purity lab) but overall, it maintains smoothness even in complex scenes, while control remains smooth, and doesn't kick in often enough to be considered a major handicap.
Keeping v-lock at all times doesn't work out so well on PS3. The further you get into the game, the more obvious the judder becomes. An environment that's difficult to render combined with several characters can see the frame-rate plummet to 15fps averages - bearable, unless you're in the midst of combat where you're battling technical deficiencies as much as your in-game opponents.
However, despite its issues, in many ways, the PS3 is trying harder than the 360 game in retaining the most intricate elements of the PC game's visuals and for that it deserves some respect.