Taron is the perfect launch coaster with no inversions; Lech is the perfect standard chain hill looping coaster. They're both at the pinnacle of what they do, but are totally different.
With that said, Lech is my number 2 and realistically deserves this more than Taron. I fear Lech may be let down by the sheer number of people who have ridden Taron in comparison and rave about it with personal riding experience instead. Lech may look less from the POV, but it will take you by surprise in reality at how insanely good it is.
Moreover, Lech is a turning point for Vekoma and hopefully the bench mark for a greater variety of coasters that can fit in lower budget parks. I'd say it's more intense than Taron courtesy of the grey out spot, it's smoother, plus you're never likely to queue long for it due to Legendia's quiet guest figures.