Hehe, took me a while to find out that in Europe R-value goes by name U-value, more commonly lambda value =) So, if we are speaking about the same thing, the smaller the value the better the insulation capacity.

For the standard mineral wool the lambda value is 0.036 W/mK ,
for the linen wool it is 0.038 W/mK - so it seems to be nearly the same.

Well, but there is a difference in price. Mineral wool is about 6.50 €/m2, and I paid 14.50 €/m2 for the linen wool. Luckily enough, the whole entrance part is that small, that it won't ruin my budget. So I can afford to pay double price for a material which is ten times nicer to handle =)

For more info in English see their web-page.

As a side-note: In Europe we use the metric system everywhere, but for some reason timber, screws, nails etc. are often measured in inches. So, the widely used timber product is commonly called kakkosnelonen which literally means "two-by-four".