arnt they roughly the same?

no, darts are cheap rubbish they supply with basic bikes, tora actually work.

In the same way that a Skoda and VW are the roughly the same. As far as I can recall the Darts have smaller upper tubes than the Tora as well as slightly lower quality components. Personally I would go for the Tora every time – worth the few extra quid for the better quality.

TORA. Get the single air version because it reasonably tunable and not so heavy. I have the coil u-turn and it's weighty and I had to change the spring too. They boing OK, are tough, and are low maintenance. Just don't expect the plushness and damping performance of a £500 fork.

Tora's are better in general, but then there are several types of Tora, and some are better than others!

tora much stiffer, 32mm stanchions vs the 30mm darts.

both pretty good forks for the cash though.

Solo air Tora would be the best bet for tuneabiliity/weight/stiffness.

Toras are much stiffer as well, 32mm stanchions instead of 28mm on the Darts, makes a big difference off road.
How much you spending and what riding/bike you planning on?

Nothing like Skoda and VW! Differences there are to do with trim and style and finish and brand snobbery.

Tora much better construction – seals won't pop out at the drop of a hat.

Tora are annoyingly good for the price.

I'd rather have rigids than a Dart on my bike.

Toras are a cheap version of Rebas

Darts are a cheap impression of a suspension fork