I absolutely agree with Allan, no need to loiter at 80mm unless funds restrict you. The only reason I did not get APM120s, which Markus said are absolutely free of chromatic aberrations, was the money. I did spend part of the difference on hand tuning as high power use was a must for me, long-term. Straight throughs are a waste, as your first pair showed you.
I like 45s, but I do not expect to go near the zenith often. 90s may be more versatile.
I don't see a learning curve, and I have myself learned that 'beginner' or 'starter' equipment just leads to frustration over money that has to be spent twice when you upgrade.
On a solid alt az mount the 100s (cannot speak on the 120s) are a breeze to use.
there are a couple of other considerations:
Travel transport: While the 120s and 100s are not enormous, they do exceed the size limit for carry-on baggage. Locating a case for the 100s was not fun, but once I looked for commercial photographic lighting cases I was able to find a reasonably priced, solidly made one, with wheels. The flaks and border guard fixed eyepiece 80s (post above) are easily packed, and I could even bring clothes! Only partially in jest, as I have transported 5" and 6" f5 achromats, partially disassembled, as well as the border guard 10x80s in carry on luggage on different trips, and still was able to bring clothes with me.
Field and Power: While the 100s, and 120s (I assume), are phenomenal to use, they do hit a wall on low powers due to the tube length/focal length. The 100s are 525 or 550 fl, and my maximum field in 1.25 eyepieces, 20mm Widescans and, I think, 24mm UFFs, still only hit about 20x-25x, 3.5-4 degrees TFOV (about, I'm not cracking out a calulator right now). The fixed eyepiece WWII flaks, and the post war multi-coated Russian BorderGuard TZKs, are both TFOV 7 degrees and 10x. Yes they 'waste exit pupil' but I understand this was done by design, to increase user comfort and speed of target acquisition. And they are marvelous to use, so comfortable, and lovely for clusters and large scale targets. I am remain surprised my border guards are still in the classifieds.
The APM 82's look like 470mm fl per APM's website, so power and field are still close to the 100s.
The Flaks manage the low power by using very short fl objectives (WWII flaks are around 275mm), oversize fixed eyepieces combined with monster prisms. They are a unique beast. Even uncoated WWII flaks are amazing.
Not to scare you off the APMs or any other big bino, but things to keep in mind.
And I am a solid APM fan, Markus keeps a tight ship on his specs and expectations from his suppliers. I assume the lesser objectives go elsewhere.