u/SandwichThen5407

Hot takes, NOT a ranking:

• Telluride: public, the best background scenery for selfie-seekers, dramatic views throughout the route, serious exposure with several sections lacking cabling, not that technically challenging but probably daunting for a first-timer, very horizontal (traverse) with minimal up/down-climbing, accessible via a moderate hike or jeep road that adds some extra exertion (the hike) for those inclined, FREE! (But I'd recommend any first-timer hire a guide).
• Ouray Via Ferrata: public, two routes (upstream and downstream) offering different levels of challenge, lots of cable pulls and footwork required (on rock vs. footholds), runs through a gorge so not as many panoramic views but still very photo-worthy, rushing water below (especially early season), varied objectives (suspension bridges, ladders, pumpy up-climbing and down-climbing sections), FREE! (But I'd recommend most first-timers hire a guide, especially for the upstream route).
• Gold Mountain, Ouray: private, requires a guide (Basecamp Ouray), directly accessible via a short shuttle from Ouray with a pick-up at the top/finish, far more vertical than Telluride or Ouray but with several sections of traversing, including some VERY pumpy sections that are optional/expert, super long suspension bridge, mining remnants throughout the route, not as scenic as others (overlooks the highway but there are some long-range views of the mountains, just not nearly as dramatic as Telluride), EXPENSIVE.
• Arapahoe Basin: private, requires a guide through A-Basin, accessible at the top of a chair lift and with a short ATV ride and hike, VERY vertical, highest elevation VF in the US, lunch at the summit with great 360-degree views, then down-climbing and a LOT of pulling on cables (gloves essential) to work your way down, LESS EXPENSIVE.
• Cloud Ladder (Estes Park): private, requires a guide (KMAC), accessible via short drive and hike to base of route, very vertical from the start, very high suspension bridges, great photo-ops but not as panoramic as Telluride or A-Basin, considered the "steepest and most challenging" in North America, but I didn't find it especially technical, just very vertical and airy, EXPENSIVE.

Fire away!