High attribute levels have a larger variety of effects, but in practice a simple modifier does almost everything that you'd want with much less fuss. There is some added complexity, but I'm not sure it adds all that much. Perhaps not surprising, given its later release, but still, I thought the "advanced" in the title signaled something.
It feels weird to say this, but BECM D&D was a more sophisticated and polished game. Like, seriously, what is "Darkness 15' Radius" even supposed to mean? It's needlessly confusing, even before you count in the fact that sometimes the text slips up and uses true measurements in the descriptions. Areas of effect use the inch = 10 feet translation regardless of where the spells were cast. If they're indoors 1 inch equals 10 feet. If your characters are outdoors 1 inch equals 10 yards. Like spell ranges being measured in inches, to represent space on a tabletop battle-mat, but then the inches themselves having contextual translations based on the conditions of the game. It's just filled with these inconsistencies and questionable choices. I can't say that I like the AD&D Players Handbook. A bit shabbier, less polished, but still recognizably the same. So my experience of reading AD&D is odd - it's like looking at something familiar in a funhouse mirror. I can't say that I read those books especially closely (mainly because I doubt 14-year-old me read anything closely by my current standards), but I did read them repeatedly. I got my start in roleplaying with AD&D 2nd Edition.