I have had a number of gassers over the years - Kalt GS, MinAir X-Cell, Hirobo, TSK, JR and now the Predator.
The best forum I have found on the net relative to gasser helis is here:
http://www.runryder.com/helicopter/f51p1/
After reading the many threads there a few years ago, I went with the Predator SE/G231 combo. I must say I was impressed. It has been very dependable ( a couple hundred flights now) and by far the best 3D one I have flown. I understand their latest NX series are even better, but I have no intentions of changing as I am so happy with the one I have.
Due to its' lower cost, specially for parts, I was surprised to find the quality to actually be better then my MinAir X-Cell GS. Maybe their newer Spectra G has improved from then, and may be as good as the Predator. I am sure you would be happy with either.
As for the Vario. It seems to be a rather robust machine. But after flying a club mate's a number of times, I was a bit let down by it's power to weight ratio, which really effects its 3D flight performance. After weighing them, I could see why. His weighed in at a whopping 17 1/4 pounds while mine at only 12 1/4 pounds!!