Could you tell us if you prefer the Calibra over the Xiom Vega or not? I never tried Stiga rubbers, but many people recommend them here. Are they very different from Xiom's series?
Yes, I prefer the Calibra LT over the Xiom Vegas, for my forehand at least.
As you may know, I played a Xiom Vega Elite before, but it got too soft and slow for my forehand. So I wanted to have a rubber with a harder sponge. The Vega Europe is harder than the Elite, but it is still soft (medium-soft) and the Pro and Asia have a hard sponge. What is missing in the Vega series is a rubber with a medium-hard sponge.
The Stiga Calibra Series has one with a medium-hard sponge, the Calibra LT. It also has rubbers with a soft (Sound), a medium-soft (Spin) and a hard (Plus) sponge, so you have a wider pallete of sponge hardness. What I don't recommend is the Boost series, especially when you are playing in a hall with high air humidity (they will lose grip).
What you also should mind is the price. The Stiga rubbers are about 10€ more expensive than the Xiom Vega rubbers.
In my opinion I would say that the Calibra and the Vega series are pretty similiar, but I cannot really compare because a played the softer rubbers (Elite and Europe) of the Vega series and the harder rubbers of the Calibra series (LT and LT Plus).
Now I hope I cleared up your question, if not, just ask xD
Btw: the long trajectory ad from the Calibra series somehow seems to work^^