THREE NEW SUBSCRIPTION TIERS!

The primary thing that the various subscription levels offer to someone who already has a lot (or all) of the books in those packages Is the AI features, which seem to be improving rapidly.  As someone who already has a huge library, that’s what I’m looking at. 
You also get early access to new or improved or fixed features, but I’m not sure they will be stable at that point so I’m not counting on that being really valuable. 
Also note that in order to USE those AI features, you need plenty of “tokens” or “credits” for each AI query that you make. The Pro package gives “thousands” whole Premium gives “hundreds”.  It’s unclear whether the Max package “thousands” are more than the Pro, but my guess is that there are. 

You also get early access to new or improved or fixed features, but I’m not sure they will be stable at that point so I’m not counting on that being really valuable. 

I don't understand your point. If the AI features are "improving rapidly" why are you uncertain that other features "will be stable at that point".

The point of subscription is that you gain access to new or improved features after 6 weeks public testing (beta test) and stability is important.

I’m not sure there is a “point”, Dave.  As 50+ year programmer I am naturally suspicious of multiple small layered releases with short beta tests. That’s my *opinion*, for my own thinking. 
The two things are somewhat different.  The AI features are being developed by a third party and licensed to Logos, so those folks have a much narrower focus and far less spaghetti-code to deal with.  So, again *in my opinon*, for my own purposes, my guess is that new AI features will be coming along more rapidly, and be less likely to be friable. 
The flip side of the AI coin is there is still a lot of internal “learning” it has to go through before it can be up to snuff re natural language search queries etc. 
Again, in my opinion, the early access to layered feature-tweaks is not what is the crucial thing for my uses. 
I am pleased about the 2-year continuous subscription assuring perpetual license to newest non-AI features.  
ymmv

 As 50+ year programmer I am naturally suspicious of multiple small layered releases with short beta tests. That’s my *opinion*, for my own thinking. 

I suspect that you, like Rosie and myself, are still more comfortable with the long analysis before coding model. One element for getting comfortable with the prototype-release model is to remember that code may be written and tested for multiple cycles before it moves into the short cycle beta testing.

and far less spaghetti-code to deal with.

I had little patience for spaghetti code ...

Agreed   And I am naturally suspicious of the “may be written and tested for multiple cycles” situation, esp in todays somewhat lackadaisical approach to things - not speaking of Logos in particular.   It’s just too easy to “fob off” the final non-crash-event testing to the users, due lot the simplicity of OTA skinny releases.  Certainly not the case in the days of punched cards, perf paper tape, and mag reels.