Engines are the very best kind of combo decks. They require effort to play, suspense (will I be able to draw that Second Sunrise?) and have a high level of interest. Let's break them down.

Engines break down into three main subtypes: - Mana Engines (Krark-Clan-Ironworks) - Untap Engines (Jeskai Ascendency) - Recursion engines (Second Sunrise) (You can argue Grishoalbrand should be on here, I choose to exclude it from this list because it really didn't fit with the rest of them. Also, you can include Waste Not, but it hasn't proven itself in the modern metagame, even if I belive it has potential.)

The Similarities Between Them: All of them need mana/cost reduction to work. All of them have a way for new cards to enter the combo equasion. All of them have cards with additional synergy with their build-around.(i.e. Ichor Wellspring: KCI Fatestitcher: JA.) And all of them have recursion (If they use the graveyard. Exeption: Paradox Engine). To sum it up: All of them need Mana, Recursion, and Cards. The deck building just depends on what your Engine of choice already provides.

The Differences: Only Mana Engines can actually produce mana themselves, other Engine type decks have to rely on other sources. This decreaases consistency slightly, as you have to find multiple pieces to combo off. Typically they are more powerful to make up for the fact (WoTC hates printig Mana Engines it seems). Mana Engines typically don't play many creatures, where Untap Engines typically want to play as many as possible. Typically both Mana Engines and Untap Engines care more about certain types then Recursion engines, but recursion engines will typically play mostly one type of card because it is more efficient for the deck. Recursion engines are the most swingy (vary greatly in deck buiilding) and least popular kind of combo deck overall. (Typically, Wizards dosn't print many competitive recursion engines. Unless of course, you built 100% competitive roar of reclimation that is.) Also, sometimes Mana Engines will play infinite combos, this dosen't make them a Hybrid though, because they have many more ways to draw cards.

These are without a doubt, the most boring kind of combo decks in existance. But they also have a habbit of winning. Let's break them down.

Infinite Combos break down into (again) three main subtypes. 1. Kiki-Combos (Includes 4c-CopyCat) 2. CoCo Combos 3. Graveyard Combos (i.e. Bubble Hulk, Necrotic Ooze.) 4. Ad-Nauseam Combo (I choose to include Ad-Nauseam because it is essentially an infinite combo.) 5. Gift's Storm (I choose to include Gifts storm becuase it really is a two card combo, once they cast gifts with a manabear you are going to die, if you have no interaction or taxes that is.)

The Similarities Between Them: The most popular infinite combos are all creature based. Of course there are plenty of infinite combos without creatures, but the ones with Chord of Calling have an instant speed tutor for their combo piece, that even puts it onto the battlefield. They all require no more then 3 cards, exepting Bubble Hulk (What a terrible name!), which really only counts as 2.

The Differences: Co-Co combos are harder to win the game on the spot with, because typiacally they need 3 pieces (i.e. Devoted Druid+vizier of remidies+Walking balista.) This hasn't hindered them yet as they can still beat you down normally. Ad Nauseam combo and Graveyard Combos can't win fairly. Most of the creature based decks have their combo pieces, and then they have their Knight of the Reliquary and Kitchen Finks. But Graveyard decks and Ad-N are more foucused on comboing off then backup plans. They are typically less resistent to hate.

Hybrids are typically the worst decks in competivity and I can't decided where they go in terms of enjoyment.

I haven't really found many examples of hybrids in MTG, but, the characteristics of Hybrids is very few (4-8) ways to get new cards in the combo, and they use a mana/untap/etc. engine to fuel 3+ infinite card combos. They usally don't relly on drawing more cards, more so just having the infinite combo. This makes them probably the worst kind in terms of winning.