The way you said "the riffs are solid, the solos are great, the drumming is tight", you can say all those aspects are executed well - that can be objective - but you can't determine how "good" the album is based on that. It's your opinion whether its good or not.
idk this is just how i see it
Album Rating: 3.0
Amusingly, the more heavily one claims quality to be subjective, the more egotistical his view becomes. You can easily determine how good an album is if you're willing to put aside the need to form your own "unique" definition of what constitutes good, and deal with reality as-it-is, i.e. outside of what you want it to be. I enjoy plenty of things that are, from an artistic standpoint, utter crap. That doesn't mean I would recommend them to others, because they are PERSONAL likes.
It also means that they are guilty pleasures, and as such, part of being human. That, in turn, means that I don't NEED to justify my liking them - and statements such as "all opinions are equally correct, all music is equally good, etc." are just that, justifications for knowing that something you like will probably be disliked by others, which makes you suspect that your tastes might not be perfect, tying your ego into knots. So, to counteract all that, you pretend to believe in ridiculous statements like "all opinions are equally correct, all music is equally good, etc." When of course, nothing else in existence parallels this view of things.
For example; if all perceptions are just opinions, and thus all equally close to the truth of any particular subject(or even that there is no "truth"), then what I am saying is just as valid as what you are saying. However, your statements and mine cannot be equally true, as they are in direct opposition. Even worse, by adhering to the fully subjective view, you are claiming that my opinion is just as good as yours, but my opinion entails that yours is not worth keeping. So you consider your own opinion to be both correct and false.
Sounds like a pretty confusing world to live in. Either "all opinions are valid" meaning that mine is valid too, and mine is that subjectivity is invalid, which invalidates the quoted statement; OR "Hyperbore's opinion is less valid" meaning that all opinions are NOT equally valid, which, coincidentally, validates my initial opinion. In short: welcome to the Liar Paradox.