I have used many mascaras, the best mascara I have ever used so far is Diorshow Iconic by Dior.
The first Dior mascara I tried was Diorshow. It gives beautiful lashes without having to apply half the contents of the bottle, pleasant smelling, and gives long and separated lashes. It is also available in a waterproof version, and a blacker version named "blackout", however I don't think the original Diorshow could get much blacker.
The price is a downer at £20 each from Debenhams, however it definitely worth a try if you have the spare cash. The mascara comes in a silver mirrored box, and the mascara bottle itself has Dior written all over the top half, so there will be no guesses who made the mascara. However I find that it is tastefully done, and if you like to flash the labels then this is a bonus (unless you use blackout, which is a plain black bottle).
Overall, I would give this a 8/10. The price being the downer, and I feel the mascara could last a bit longer on the lashes then it does, and the first few times you use it so much product is on the brush that it clumps a little. I still think that it is worth a try, I think it will probably go on different for different people :]
Now, Diorshow Iconic is a whole different matter. I thought the only difference would be that it gave a bit of extra curve in comparison, but the brush is completely different and so the effect is completely different. I found it never clumped, the lashes were a lot more separate and also longer. The bottle is silver with Dior embossed all down it and has Diorshow Iconic and Dior written down the side in black. The box is just the same as the regular Diorshow. It also comes in a waterproof version.