I got mine today. Build first a 3mm coil, 26 ga Kanthal, 8 wraps. I must have messed up the wicking as it was leaking like crazy. Then, I ripped it apart and build using a 2.5 mm bit, so it had more space. It still leaks, especially after fill-up.
The wicking is not for the faint of heart.

You really need to get that down.
My impressions: not a lot of airflow, issue with leaking and wicking it takes some time.
Compared with Lemo2. Lemo2 comes on top (for me). YMMV.
To be honest, I did not "heart" Lemo2 in the beginning, but I guess, as I worked on it, I learned to do the wicking just right. I guess Cthulhu may be the same. It is my first double coil atty.
My advice: wicking offten in the begining until you get good at it. Watching youtube videos may help too.
I'm not impressed.