[Continued from Basically Why Basic.]
First, the advantages of Basic/Expert Dungeons & Dragons (practically speaking)...
1. Favorable and Simpler Spellcasting
A magic-user must have the freedom to speak and gesture in order to cast a spell, but there are no "material components" to worry about procuring, expending, or recording. The casting time for all spells is one round, so that simplifies the process and reduces rulebook consultation.
2. Favorable and Simpler Spell Memorization
After an uninterrupted full night's sleep, a magic-user requires only one hour to re-memorize all "erased" spells. It's a better rate of recovery and it's uniform.
3. Favorable Ranged Weapon Modifiers
Ranged weapon attacks are +1 at short range, normal at medium range, and -1 at long range compared to AD&D's normal at short range, -2 at medium range, and -5 at long range. Is Basic/Expert D&D generous? Perhaps, but the odds of hitting an opponent at low levels is already ridiculously difficult in D&D. In light of that, I don't think the Basic/Expert modifiers are unreasonable (and it might reduce player frustration).
4. Simpler Alignment System
Three alignments instead of nine. Let the rules demand allegiance to one of the three, and let the players work out the subtleties for themselves.
5. Simpler Spell Descriptions
Simpler spell descriptions are more quickly and easily understood and remembered by players, which means less time is wasted consulting rulebooks. It also gives more freedom to DMs and players to add their own twists to the spells, either in how they function or in their "flavor."
6. Simpler Weapon Damage
Each weapon causes one range of damage regardless of the size of the foe. This reduces complexity and also allows more kinds of weapons to be conflated. The added benefit of this is that a player is likelier to choose a weapon that matches a vision of the character rather than being distracted by a minute examination of relative advantages and disadvantages. The simplification of weapon weight and the absence of weapon speed modifiers also contribute to this benefit.
7. Simpler Weapon List
A simpler weapon list, in addition to the benefit described above, means that players will spend less time trying to decide how to arm themselves. It also means they won't need to research obscure polearms. (Personally, I enjoy researching obscure polearms and all sorts of arms and armor, but it's a wee bit more academic than is required for a game of exploring dungeons and stealing treasure from dragons.)
8. Streamlined Classes
Simpler classes encourage quicker character creation. They are also less intimidating to new players. Perhaps even more importantly, they are not weighed down with fiddly special abilities and rules exceptions that often go ignored by players who can't keep track of them all. With simpler classes, DMs and even players are free to interpret them in their own unique way.
9. Superior Organization of Rules
The Basic and Expert rulebooks may not be perfect (they are divided into two rulebooks, after all), but they are organized in a way that maximizes ease of learning, which is a tremendous advantage if one wants to introduce more people to the hobby. It also contains pretty much only that which is essential. Some rules may be lacking, but they can be easily extrapolated or invented, and this is one of the greatest advantages of Basic/Expert over Advanced. Some of the rules you create to meet the needs of your game as they arise during play are amongst the best rules you will ever use. There are plenty of Web logs in this hobby proving that point daily.
10. Absence of Weapon Proficiency Rules [added 23 March 2013]
I did not realize when I first started playing D&D what a blessing it was not to have to worry about certain things. If I played magic-user, there were few weapons I would be able to wield; if I played a fighter, I could wield any weapon I could buy, find, or otherwise obtain. It was one of the perks of being a fighter. AD&D weapon proficiencies put a stop to that fun. Rather than describe everything I find repugnant about those rules, I'll just pose a simple question: In what way do weapon proficiency rules contribute more fun to the game than they detract from it? I rest my case.
Next, the advantages of Advanced Dungeons & Dragons (practically speaking)...
1. Favorable Hit Dice for PCs
There's no doubt about it, I prefer the class hit dice in AD&D. I like the idea of each class having its own hit die type. I like the fact that a hard-living thief has a slightly larger hit die than an academic magic-user. I like the fact that a clean-living cleric has a slightly larger hit die than a thief. I like the fact that all of them except the magic-user have a marginally better chance of surviving in a fight. When I play Basic/Expert, I prefer to keep the Advanced hit dice.
2. Favorable Spell Acquisition for Clerics
If ever a party desperately needed a cleric with the ability to heal, it's at first level. I can fathom no reason to withhold the spellcasting ability until second level. Therefore, I don't.
3. Negative Hit Points
In some cases, I can see instant death resulting from a blow, but in a great many cases there is a period of incapacity or limited capacity before death occurs and during which stabilization and later recovery might occur. Sometimes the wounded lie bleeding until they die. Sometimes help arrives in time. That's why I don't mind the negative hit point rule of AD&D. It may not be perfect, but I think it's on the right track. There are many variations, and I'm giving some thought to my own.
Needless to say, I decided to run Basic/Expert with a few Advanced modifications. I'm quite partial to many of the spells and monsters of AD&D, so many of those will be transferred, too. If Labyrinth Lord were published in an edition that incorporated the Original Edition Companion so I wouldn't have to switch between the two books, the work would be done for me. Alas.