Great bikes, parts availability / dealer support is the biggest drawback I've heard. You might want to check RMDRA there are a few Calgary based guys their with GG bikes
Parts avail should start to improve very soon. The new management really wants to break into the N/A market and is the process of recruiting dealers, and re-structuring the network. A LOT of parts on these Gasgas enduro's cross over with more common bikes, combine that with some aftermarket coverage and most of us are fine for parts while they attempt to expand and grow.
I've heard they are great bikes, much like the Beta in style I've heard? The company went bankrupt (spanish owned) but were bought out by an Italian company I believe. So far so good under the new ownership i think.