I like the different colours included and the style of the pens. The only thing I did not like about them is that the colours are not strong enough so I you write on bright paper, the colour is missing.
Great fineline pens, which offer different colour shades to the Stabilo pens I also have. While, at only 12 colours, these are obviously limited, if you're looking for an accompanying set to a larger collection, or maybe only need a handful for small notes/projects such as scrapbooking etc (which is what I bought these originally for, despite now using them for colouring) then they're perfect as they are. The very cheap price point is also a great factor.
The pen quality itself is also top notch. Fine enough that it's easy to be controlled and accurate, strong enough colour that you don't need to press too hard but also a consistent ink flow.
Seems quite expensive but we bought these for our Wedding presents (DIY scrapbooks) and we coloured in full pages and there is still ink remaining, lovely vibrant colours which dry fast. Lovely buy. The yellow isn't fantastic, can hardly see it but the others make up for it.