For what it's worth, I was taught one stage of flaps for take-off from hard grass in a PA28, although I can't find reference to that anywhere in the POH. However, standard short/soft field technique in the POH is 2 stages, so I can't see that 1 stage could be considered dangerous. On muddy grass (e.g. White Waltham in the winter) I use the POH soft-field technique. On a touch+go, I retract the flaps to one stage (or zero on a hard runway) after landing.
Taking off with full flaps in most types seems dangerous - it will definitely extend your take-off run compared to whatever the normal short-field technique is (usually one stage below full flaps), and there are no published figures to give you any idea how long the take-off run will be. Having said that, if this is what you've been doing since you started in the circuit, it may be more dangerous to change your habits now, especially without an instructor sat next to you...
As for the original question, in a tricycle I prefer hard runways every time. Grass is more bumpy, but not really any harder - just different. In most tail-draggers, I prefer grass every time. I tend not to look at the ASI during take-off in a tail-dragger, I rely on the responsiveness and feel of the controls to tell me when the aeroplane's ready to take-off so I can keep my head out of the cockpit. Being bounced around a bit on the grass provides a lot more clues as to what's going on. And during landing, if you've got even the slightest amount of drift or yaw when landing a tail-dragger on a hard runway, you'll know about it, and you'd better be quick on the rudders! The Europa isn't a normal tail-dragger, though - and although I still love landing it on grass, I'd rather take off from a hard runway, given the choice - the technique is much more difficult, but it's also more forgiving. (But it's not often we have the choice!)
FFF
-----------------