I have both, and I love both of them, but if I had to choose, it would be the ares, hands down. The zenith is a nice, large capacity MTL tank that has plenty going for it, but to me it's not "revolutionary" or anything, just super nicely designed and well constructed. To me it's a solid choice for a drop in tank, but I wouldn't say I reacted to it the same way I did my Kabuki, for example.
The ares flavor is just fantastic, it's an easy build, I have been vaping the HECK out of mine and the way it's designed and the capacity... I am still on my first coil AND wick (rayon) but I vape it a LOT. It's also got a lot of design elements going for it.
I would say, as a first RTA, it's a good choice now that they worked out the initial problems with condensation in the chimney. It's an easy build, SUPER easy, I built mine the first time in 20 minutes. I watched a review video, but it really wasn't necessary. It's got to be going on a few weeks, now.... And it's fantastic! No leakage, not a drop. I would hands down try the ares, but both are good choices in my opinion.
I ordered a second ares. I didn't order a second zenith, let me put it that way....
Anna