Ive never seen or tried one personally but there are a few getting around here in Oz and being made by Nuova Simonelli, I dont think there would be any risk about build quality. I guess you just need to think about local service and support, etc as you wouldnt want to be buying an orphan and have to rely on o/seas agents for support.
Having said that though, I dont think its likely that you would experience any problems with the Grinta and if the model youre looking at is the version with the timer, well, I wouldnt be relying on that too much to determine dose quantity as various coffees and roast levels, etc will always make trying to use the timer to dial this in a bit of an exercise in frustration.... thats not just for the Grinta though, applies to all similar setups. One advantage over similar price-point grinders though, is that the Grinta has relatively fine adjustment steps and that is a definite advantage with espresso. Theres a decent review of the Grinta here at CoffeeGeek.....
The Imat Lux you mention is a good quality and solid little grinder too but not ideal for espresso as the adjustment steps are quite large and can make dialing the grind in for a perfect pour a bit difficult. Notwithstanding that, it is of a solid build and uses an excellent burr-set