It is subjective
Given that you have already ruled out the classic HW and/or UAE, then you are looking for a NG solution. Given that you have also ruled out AROS, then the choice is between OS4 and MorphOS, and *there are* some perfectly valid
objective points of measurements to help you make up your mind (I think Fab managed to relay what I wrote pretty accurate, don’t remember exactly though).
MorphOS *is* faster, it *does* have all the preferred by most and most widely spread Amiga standards integrated and in modern versions, it *does* have a much lower system cost, it *does* run on easily obtainable mainstream hardware with totally OK bang/buck ratio, it *does* have the best Amiga compatibility, it *does* have the most and the best features as a whole – the desktop, the shell, 3D, JIT, etc, etc.
These are objective, measurable, comparable facts. Nothing subjective about it at all. You can make speed benchmarking charts, you can write feature charts, you can make compatibility comparison charts, you can make price comparison charts, and you can put them (the OS4 and MorphOS charts respectively) side by side, in black on white, and then you can draw your conclusions from that.
*OR* one can do as *You* did, and completely discard even the thought of objective, rational comparisons with a simple "it’s entirely subjective" one-liner sentence (making some weird analogy to MS-DOS vs. Windows 7 on top of that (!!!)) – Well, of course you are *totally free* to "want" the slowest system, the solution with the second class left-over Amiga standards, tied to insanely priced low volume hardware, worse Amiga compatibility, worse desktop experience, worse shell experience, worse 3D, worse JIT, etc, etc. But in my book, that is *not rational*, and it's like saying ”I prefer coal power plants instead of power plants that doesn't contribute to the grow house effect, because that's how I want it, and it's entirely subjective anyway”, ”I like slow, expensive, dangerous, polluting cars with no second hand value instead of fast, cheap, safe and environment friendly cars with a high second hand value, because that's how I want it, and it's entirely subjective anyway”, ”I prefer war instead of peace, because that's how I want it, and it's entirely subjective anyway”, etc, etc.
In that sense *everything* can be ”entirely subjective”! But that doesn’t take away the fact that *purely objectively* speaking, using rational comparisons, peace *is* better than war, safe and clean cars *are* better than unsafe polluting cars, and non-polluting power plants *are* better to the environment than coal power plants.
If you would *actually do* an objective comparison between the current best OS4/MorphOS systems, and come to the conclusion that no matter MorphOS's superiority when it comes to price/performance/specs/compatibility (which is the only conceivable outcome) you simply want the OS4 one anyway,
*THEN* we are probably talking about a decision made on subjective factors, like taste, emotions, your need of belonging to a certain group, or whatever, instead of purely objective factors based on verifiable facts. But that doesn't say it's impossible to do objective comparisons between OS4 and MorphOS, it only say that
*YOU* chose *not* to!
It's *NOT* "entirely subjective" to everyone!