Its good kit, particularly if you have the antartica block. 10mm OD tube works fine and it pretty standard with a lot of German* systems. You can also use components from other manufacturers if you stick to 10mm pushfits (and preferably 1/4 or greater thread).
My system evolved form an early WaterChill kit and now has components from about six different Manufacturers.
You can also buy the same kit with 1/2" OD tubing in some shops, but it's harder to find attional fittings for these in Europe and would probably be most relevant if you were mixing components with swiftech who use 1/2" pushfits.
You'll find a few suppliers in
this list I have three for Sweden, but many of the european shops will deliver anywhere with EU.
*(Yes, I know Asetek are Danish but the competitors are mostly German)