Yeah, I find the Gateron blacks to feel noticeably lighter than Cherry blacks as well. I prefer heavy switches & Cherry blacks are just heavy enough for me with their stock spring, while Gateron blacks are definitely too light for my liking with their stock spring. I believe Hyde is correct with his weighting info. Although there are pros & cons for both brands, weight isn't a huge consideration considering you can get aftermarket springs to make either as heavy or light as you like.
The Gateron blacks are smoother than Cherry blacks, but Cherry has retooled their production line & now the difference in smoothness is much less of an issue. The new Cherry blacks are very smooth compared to pre retooling blacks. Then Gateron switches have more wobble than Cherry switches which can be pretty apparent if you're using higher profile caps like SA or even OEM due to how tall they are. This is due to Gateron having slightly looser tolerances than Cherry. Basically all the parts in a Cherry switch fit tighter together causing more friction with key presses hence them feeling scratchier. While all the parts in Gateron switches have a tiny bit more room with each other, which causes a smoother key press feel, but also a noticeable wobble of the key cap on off center presses.
This carries across the whole regular Gateron line up when comparing to their Cherry equivalent. Gaterons will be smoother, a bit lighter weighted, & more wobbly than their Cherry equivalents. This doesn't carry over into Gateron silent switches apparently though, as they have been reported to be pretty scratchy & haven't reviewed to well AFAIK. No personal experience with them yet so YMMV with them.
