Gennies are a difficult attie to get working well because they have a few issues and any single one will make them unusable.
The biggest single issue with them is getting the ss mesh oxidised properly, this really needs to be done perfectly or else it will give you hotspots/burning taste/shorting and its not immediately obvious that the mesh is the problem. They also suffer from wicking issues as the wick can be too tight in the holes or too loose which will make them flood or else the coil can be wound too tight choking the wick causing bad wicking or too loose causing burning and some of them will never wick well and you have to tip them upside down when you want a vape to get some juice to the wick. You can make a U wick which I have in one of my genesis type atties and it helps but still doesnt cure it and they still need tipped to get juice to the coil.
You can get a top fed attie (I have one of these too) but then a lot of people dont like these as the vapor has further to travel to the mouthpiece/driptip which in turn makes them have a cool vape and a lot of people dont like the cool vape.
Ody and Penny on the other hand take you to do something pretty disastrously wrong for them not to work like a champ right from the first attempt and they dont leak where gennies do because of their design and there is no way around this.
To some Ody didnt hit as hard as some of the best gennies BUT Penny being smaller hits as hard as the hardest hitting genny out there, I own one of these gennies and honestly Penny hits as hard but has NONE of the issues gennies suffer from.
In short if I were to start over again with rebuildables what I would do is get a Penny first as you have a rebuildable that is easily built,works perfectly,is really frugal with juice consumption (some gennies absolutely guzzle juice at a terrific rate) and you wont be caught dying for a vape and cant get the damn thing working which I have seen on boards numerous times! and then dabble in gennies if you feel you really need to but in all my experience only the very very best gennies vape as well as Penny and honestly none vape better.
Its statements like these that make me sane again and not lose all hope on using a rebuildable. I'll be posting back on my impressions about the Penny coming from a noob ex genesis owner