[glend (Glen)]

First off let me say that I completely understand the role that "passion" has in buying decisions; heck it keeps Shannon's in business ( ie cars). You don't give us any background on your experience with astronomy, and that is a factor in any advice people might offer. My personal opinion, based on chasing my passions for seven decades is buy neither, those are, in my opinion, overly expensive scopes with limited resale market interest. You will always lose money on selling scopes, and frankly neither of them is much better visually than say a 16" GSO dob or a Skywatcher. Minimise your investment and potential resale loses. Sure they are nice to look at but your buying a tool, an instrument to look at the night sky.
Be honest about why you want a large dob. Are you buying it to impress people at a star party in the daylight, or you just want something that works. It is easy to add guiding systems like Astro Devices Nexus to a GSO dob or go for the Skywatcher Goto version.

Disclosure, I owned a 16" GSO dob for years, and on occasion have looked through similar "custom, ie expensive" offerings, including very large SDMs.