I think it's an inferior design that results in an inferior vape. They've ripped off the Advken CP TF RTA but badly. What advken did right is include bottom airflow as well as keep the wick length short. The top row of air holes on the X's chimney don't help things either. I've owned literally dozens upon dozens of rtas. They are my "thing" and always have been since I started vaping. I'll take a quality rta over an rda any day of the week. So I know how to build and wick an rta. I've helped many members here since I joined to tweek their builds and wicking to get the best out of their devices. I just find the X gives an inferior vape even when it's wicked optimally. Does it give a "decent" vape? Sure. Does it compare with the best rtas and give a truly saturated and lush vape? No, not at all. I've toned it down over the last six months but I used to have at least a dozen different vapes on the go at any one time with different kit constantly rotated in and out. The X wouldn't have even made it in to my top 20 and certainly wouldn't have dethroned any of my favourite or established vape setups including the Bravo, Blitzen and Triple 28. I've still got those 3 tanks whereas I sold the X.
The original Zeus was a cracking rta. One of the best. The Zeus dual was also very good but was very finicky with coil position making a big difference. Still a quality vape tho. So I had *extremely* high hopes for the X as it's one of the sexiest tanks on the market, IMHO. But I was *extremely* disappointed. The only other rta I've ever bought that had me that disappointed was the Crius 2 dual. Another rta that couldn't come close to its predecessor; the Crius 2 single coil rta.
I love the look of the X. It's sexy AF. I gave it every chance to impress me. But I'm sorry to say that it didn't. And I really wish that it did.
TL-DR
I don't like the airflow and whoever at Geekvape designed the X should be whipped for designing an rta with wicks that are longer than my driveway.
The X just doesn't compare with the best rtas regardless of how you build and wick it. There's literally dozens of other rtas and rdas that I would choose over it.
But vaping is incredibly subjective. YMMV.
There's really only one solution. For the OP to buy all 3 and decide which is best.