Sorry, I have experience only on the Gene so can't give you comparative opinion. Not aware of alot of folks that have owned both the Gene and Hottop.
I would pull the trigger on either and not look back. Both have good reputations. Posters with difficulties with both on Coffee Geek are typically outliers, not mainliners. If you go with the Gene, I would encourage you to cool externally (I used a collander, bucket, and a small shop vac to cool in 45 seconds). A Hottop advantage is that is built-in feature.
Gene Cafe gathers an 8.8 avg at Coffee Geek from 15 reviews from consumers.
Hottop gathers a 7.3 avg at Coffee Geek from 22 reviews from consumers.
I can't account for the difference since I don't know one dissatisfied Hottop owner on this forum.
B|Java