When comparing Dungeons & Dragons 4th Edition vs Monsters & Magic, the Slant community recommends Monsters & Magic for most people. In the question“What are the best tabletop RPGs?” Monsters & Magic is ranked 42nd while Dungeons & Dragons 4th Edition is ranked 61st. The most important reason people chose Monsters & Magic is:
The game uses a single core mechanic, which is flexible enough to cover a wide variety of situations. This helps GMs immensely when characters want to do things that aren't already covered in the system. The mechanic itself works thusly: all rolls are 3d6 + modifiers *minus* difficulty. The result is how many effect points the player can apply to the action -- or, if negative, how many consequence points their opponent can apply to a reaction. Dealing damage is one use of effect points, but there's a limit on how much can be dealt at once, so additional effects (e.g. distracting, disarming, unmounting, etc.) see constant play instead of only being used rarely or by super-specialists. This also means failure is interesting, since it results in consequences! This mechanic is used to do everything, and the game essentially consists of nothing but examples of how to use it.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Concise and consistent rules
Compared to prior editions, 4th Edition D&D has dramatically simplified rules. There are very few special cases to remember, and all character classes (Fighter, Wizard, etc.) share a common pattern in how they gain and use combat abilities.
Pro Excellent tactical combat system
As a grid-based combat game, 4th Edition offers well-balanced and tactically rich gameplay. In particular, it features numerous effects which force or prevent movement, often preventing simple "charge and attack" tactics.
Pro Focus on heroism and fun
4th Edition downplayed simulation, and instead embraced cinematic action. The players are assumed to be the main characters of a story which revolves around them, rather than merely one faction in a far larger world.
Pro Best balanced version of D&D
Other versions of D&D tend to use a "balance over time" system, where some character types are weaker to start with and stronger later on, and vice-versa for others. However, this works poorly if your game doesn't continue for a long time, or starts with PCs already at a higher level. 4th Edition is the first - and so far only - version of D&D to do a good job of making characters similarly powerful at all levels.
Pro Character death is uncommon
To encourage boldness, characters are far harder to kill than in any other edition. This also allows players to invest heavily in the story and personality of their characters without facing the potential buzzkill of loss.
Pro A unique D&D experience
Not weighed down by sacred cows, and arbitrary rules for the sake of nostalgia and identity.
Pro The Effect Engine
The game uses a single core mechanic, which is flexible enough to cover a wide variety of situations. This helps GMs immensely when characters want to do things that aren't already covered in the system.
The mechanic itself works thusly: all rolls are 3d6 + modifiers minus difficulty. The result is how many effect points the player can apply to the action -- or, if negative, how many consequence points their opponent can apply to a reaction. Dealing damage is one use of effect points, but there's a limit on how much can be dealt at once, so additional effects (e.g. distracting, disarming, unmounting, etc.) see constant play instead of only being used rarely or by super-specialists. This also means failure is interesting, since it results in consequences!
This mechanic is used to do everything, and the game essentially consists of nothing but examples of how to use it.
Pro Interesting combat
Attacks generate effect points, which you spend to do things to your opponent. However, the amount of damage you can do is limited, which forces players to do other things... and the effect system is broad enough that these can be things like cutting off a carrion crawler's tentacles, knocking an opponent's sword out of their hand, and so on. Failures on attack generate consequence points as well, which your opponent can use to do things to you.
Pro Mental defense and hit points
Characters have a "Mental Defense" score and "Mental Hit Points". These are used to help provide a unified system for handling social encounters and mental attacks via magic.
Cons
Con Too much focus on combat, not enough on roleplay
Con Ovely complicated
Con Not enough customization
Multiclassing has been reduced to the point where it is rarely useful past the first feat & limited to one extra class.
Con Combat drags
Due to the scaling of player damage vs. monster hit points, even simple fights can take a long time to resolve, particularly at higher levels.
Con Suspension of disbelief is often difficult
Making it fun was such a priority in 4th Edition that it frequently trumped making sense. This manifests in ways ranging from "minions" who die in hordes at the lightest touch, to broken weapons simply repairing themselves.
Con Grid combat is required for best combat experience
Though most other editions of D&D assume miniatures are used for combat, they have all provided rules for playing without them, while 4th edition has not. It even goes as far as to measure distances and ability effects in terms of "squares.".
And while it's possible to play the game without a grid, 4th edition combat places so much emphasis on powers and abilities that move you and your opponents around the battlefield that keeping track of such movement is important enough where playing 4th Edition without minis or a similar system loses most of the interesting parts of the combat system.
Con Equipment is mandatory to be efficient
Con It's the easy mode of D&D
Everyone has spells and unlimited HP.
Con Not currently available in print
Is only available in PDF.
Con Few monsters & spells provided
The included rules have only about 20 monsters and 1st and 2nd-level spells. Third party publishers have supplements that provide more, or you can use ones from old D&D.