My experience is limited to watching a friend play them back in the day, and him letting me tinker with a "new game" to see if I would want to play it myself. I was a huge D&D tabletop fan, but I never got into the AD&D ruleset that Gold Box is based on (I spent 20 years away from D&D in general, going from Basic to 4E between the ages of 18 and 38). I was often confused (and sometimes perturbed) about multi-classing, dual-classing, and level limits based on whether or not you were a human. In retrospect, I don't feel like I fully "got" the AD&D ruleset, and thus never had much interest in learning it to play the game(s). Having played Basic, 4E, and some 5E, I feel like AD&D may have been the most difficult to learn of the rulesets.
I enjoyed the visual customization of each character's icon, as far as race, outfits, weapon, shield (or no shield), and colors. It felt very groundbreaking at the time, especially with games like The Bard's Tale where you didn't get to choose a portrait AND you didn't even get an icon because there was no battlefield. And who doesn't enjoy "rolling for stats" when creating a character, hoping to score big with a powerful fighter or a super-dexy thief or a genius mage who gets extra spell slots?
What I didn't like was THAC0 (like most, I have many complaints about it), having to "8-hour rest" & then memorize all our spells (hoping not to get "interrupted" and have to start over again), manually mapping (which I suppose is no longer an issue, as the maps are likely all over the internet by now), and the view during combat.
Let me elaborate on the combat thing. I'm not talking about the EoB series, I mean the games in Bundle Two. I liked that the battlefield was grid-based, but I didn't like that room walls were slanted...it messed with my perception of where I could and couldn't safely move. I also didn't like that I couldn't see the entire battlefield (I had no way of knowing exactly where everyone was, friends or foes).
As far as the stories told in these games, I can't comment at all since I never played them and I never read the novels they were based on. I did, however, enjoy the hell out of playing tabletop D&D in Basic & 4E (by the time 5E came around, I had tried it for a while but didn't like having to adapt to yet another new system...it actually seemed like a good system, I just didn't have the time/patience to learn it thoroughly).
So if anyone wants to agree/disagree with me on something, feel free. Admittedly, I may be remembering something wrong, or something may have been made easier as far as gameplay as the Gold Box series games were originally released. These are games I definitely feel like I should enjoy, but I think mostly because of the ruleset and battlefield, I'm still undecided on whether to buy them.