What would be the pros and cons of an AT classical cass vs. a SCT?
Pros: cheaper, better stray light control (baffles), no mirror flop or changing focal ratio with fixed mirror, sharper on axis, better focuser, easier cooling, less dew issues.
Cons: not flat or coma free like an Edge, far tougher collimation, heavier, diffraction spikes, open tube means more cleaning(how do you properly clean the primary?)
What else? I'm no expert.
I bet the optics will be great, so long as the mechanics are quality it will be a great offering. I think the mechanics will be key as they are going to be more important in a classical cass than in a normal SCT.
I migrated to a classic cass (CFF350) after 35 years of owning SCT's. (C8/C11/C14HD) I'll speak to my classical cass observations, perhaps some of the AT features will be similar in nature.
I actually find collimation easier than my SCT's. CFF integrates 3 collimation knobs on the rear backing plate. Each knob has a graduated ring so you can keep track of adjustments. All of this makes adjustments more intuitive since you can align the primary vs the resultant Airy disc looking up at the back of the OTA. No more hanging over the secondary this way trying to figure out which way to adjust. If the rings get confusing, I can remove the baffle and it makes interpreting them much easier. I suspect a truss design makes this easier to do though. Diffraction rings will look a skosh dimmer with a 22.5% CO but my 11mm TV Plossl does pick them out. (good seeing of course) But yes I like the lower CO%. The collimation is rock solid - I don't need to adjust it for a given imaging angle - even after 100+ setups in the past 3 years. I was surprised how rigid trusses can be and of course an open tube should be great this way as well. Initially when I received the scope, I did measure my trusses to design spec, then HG laser + Tak scope. This with final star collimation and I don't seem to notice any astigmatism.
Diffraction spikes are not an issue either. (at least to me)
The primary does need to be cleaned more frequently maybe like a Newt, but unlike an SCT, you can "get to the engine".
Primary focus is the secondary and is very tight. No mirror flop this way. Secondary focus is a Moonlite in my case. I should note CFZ is considerably more with a classical cass. I find this beneficial when imaging as I have much greater focus depth than my C14HD did. (f/17 vs f/11) Also this results in a bit more back focus, so technically my imaging train can be a bit longer if needed.
High f ratio benefit for imaging. I do planetary imaging and with low planets need an ADC. ADC's usually need min of f/15 to work properly. That usually means barlow before ADC, but a barlow can then cause unwanted barlow amp and reduce frame rates dramatically. All of this is negated with an f/17 classic cass. No barlow needed as I'm imaging with proper sampling. (~5x of pixel size) Just ADC and be happy with a simpler imaging train.
It does UV image a bit better without a corrector plate. And I don't worry about corrector dew formation this way any more. (which reduced frame rates)
The OTA weighs a few pounds less than my C14HD OTA. It does have a longer moment arm, so carrying it out is a bit more work. So be prepared for this of course.
But I think the icing on the cake is the ability to do a boundary air sweep of the primary. (open tube/truss) My CFF has 3 rear fans that cool the primary and then this air flows out and around the mirror across its front side. This stabilizes the image nicely especially during instances of night time cooling. Shut them off during cooling, and the image degrades somewhat. Turn them back on and ~15 sec the image clarifies again. In comparison, I owned a closed tube C14HD with Tempest fans, which I'd recommend for SCT's. But I never could get the image this stable this quick with the C14HD fans on. (usually hours) So this is another benefit to open tube/truss.