looks like the Thunderbolt has been getting good reviews
so longer top tube and shorter stem like genesis, but with slacker head angle.
seems like front centre will be much longer, but steeper seat angle will keep riders weight centered while sitting
my partner is thinking of the Thunderbolt because she can't seem to weight the front of her 29er enough (she already has changed to a 100 mm stem on a small frame and any longer stem or lower bar will hurt her back)
should smaller/lighter riders go one size smaller, or flip stem and slam the bar to keep weight on the front wheel