Gamers Nexus has a review on an older revision for a Dual Tower, i would take a look at it. Problem with comments online it that no one stop to say good things, so usually it's going to be about bad experiences, if you take a look on the PS120SE for example, there's 4-5, maybe more Thermalright direct sellers, all those pages have reviews, so at least 1000-1500 reviews say it's at least 4.5/5, that's really good.
About the SSD, is not that's incompatible, as PCIe is backward compatible, it's only that for $5 more you get a better SSD. The 980 PRO is at it's lowest price so far, i would grab one.
I would go for the ASUS, it has less length, won't be sagging as much, has bigger fans, meaning they are going to be a bit more silent at full speed. 3 Fans usually are a bit smaller, meaning they can reach higher RPM, so they can be a bit loud.
4 fans is more than enough, with the components you are going for you won't have any cooling issues, even with 2-3 fans on the case, it's mainly for visuals.
But... yes, more fans would help a bit, if you have 4x fans, maybe grab two fans to use them at the top of the case to help exhaust air. If you live in a hot place, better airflow will help extracting hot air and keep temperatures under control.
Likei said, save money on some itens, and either grab 2 of those fans, or go for something even cheaper, Thermalrigth has a bunch of 120mm RGB fans (and packs) for under $15