Are the Guilds of Ravnica Guild kits worth buying? I don't usually do these style of articles because it's often pretty clear who the target audience is for the product. These are a little more off the beaten path and blur some lines between audiences. I think overall that is a good sign for the product because cards that appeal to more than one group are often the most desirable.
Let's start off with the basics. Guild kits are 60-card Preconstructed decks that will be available for purchase November 2nd. They all feature a foil alternate art legendary creature and guild specific basic land art. Each deck comes with 8 of each basic that guild uses (ex the Boros deck has 8 plains and 8 mountains). The 5 guilds in Guilds of Ravnica (Golgari, Izzet, Boros, Selesnya, and Dimir) are the only guilds represented in the guild kits. There will be another set of guild kits for the remaining 5 guilds after the release of Ravnica Allegiance (as confirmed by Senior Designer Gavin Verhey here). The cards included in the decks are from every Ravnica set including Guilds of Ravnica. And finally the MSRP is $19.99 in the US.
$20 for a precon is not terribly expensive. Duel decks had an MSRP of $19.99 and could be worth purchasing; but, often at the time of release were lack luster. For the same $20 you only get one deck. However, based on the decklists, we can easily tell these are much better decks than recent Duel Decks. If you'd like to take a look at the decklists to follow along, they are here.
Izzet
We're starting off with the softest deck here. From a purely value perspective, the cards inside are worth about $30. If you ignore all cards worth less than $2 you only end up with 2 cards. Stitch in Time is $6.50 but it is expensive because it is rare and not because it is particularly popular. The other expensive card is quite popular and rare and is Shattering Spree. At $12 I would expect it to fall a little, but it will likely retain most of the value of the box set. The biggest thing this deck has going for it is that it contains the Izzet themed Islands. Currently I do not see any stores offering a preorder price for the basic lands so it's really hard to predict where they will end up. My guess is that these will retail for $0.50 to $1 each depending on how much people like them. They're not full art but given the amount of choices people have for full art lands these days, I think it's better that they're not. They're also not foil. Those will be available in very limited supply the weekend after the release of the guild kits. Overall, I think this is the worst of the 5 decks but is perfectly serviceable if you like Izzet or just want the get the legendary creatures in the new border.
Golgari
The Golgari deck's retail value is pretty similar (also about $30) to the Izzet deck but it is less focused. The cards over $2 currently in the deck are Deathrite Shaman ($4), Savra, Queen of the Golgari ($2.50), Sisters of Stone Death ($2.50), Abrupt Decay ($4), and Deadbridge Chant ($3). Unfortunately, unlike the Izzet deck I believe that most of these cards will continue to see declines. Deathrite Shaman isn't legal in most formats, Abrupt Decay may become usurped by Assassin's Trophy, the legends are expensive because they're old, and Deadbridge Chant was a mythic. It would not surprise me if most of these cards saw pretty big price drops because their price is almost entirely predicated on their rarity. This deck has 4 legendary creatures instead of the two that Izzet has, so overall I give it a little more of an edge. It will appeal to more Commander players than the Izzet deck.
Dimir
The Dimir deck is a bit better than the first two and has about $38 worth of cards currently. The headline reprints in this are Glimpse the Unthinkable ($6.50), Mission Briefing ($8.50), Lazav, Dimir Mastermind ($2.50), Circu, Dimir Lobotomist ($2.50). While Mission Briefing is currently quite expensive, I think that a lot of people think it's much better than it is. Due to the fact that these are releasing so far after the set release I would be surprised if Mission Briefing was more than $1 at the release of the Guild Kits. Overall I think Dimir is one of the better constructed decks. It has 5 legendary creatures with the new border and is a pretty reasonable starting point for a mill deck. I think this is the most medium deck of the bunch.
Boros
The Boros deck has a current value very similar to Dimir at around $36. I think it has many more reprints that will withstand dropping a ton due to a reprint. The headline cards at $2 or more in this deck are Legion Loyalist ($8), Swiftblade Vindicator ($2), Legion Warboss ($4), Aurelia, the Warleader ($6), Lightning Helix ($2), and Boros Charm ($2). These reprints are Modern mainstays, Standard hopefuls, and Commander All-stars which is a recipe for success. Lightning Helix and Boros Charm are unlikely to see any price movement as they haven't the last few times they've been reprinted. Swiftblade Vindicator and Legion Warboss are both in Guilds of Ravnica but I believe have a lot more potential to be successful. Legion Warboss in particular seems to be compared to Goblin Rabblemaster which was a particularly potent creature during its life in Standard. I don't foresee these cards becoming much cheaper. Aurelia, the Warleader and Legion Loyalist are casual all-stars that bring a lot of unique abilities to Boros players. There is nothing quite like them and despite Aurelia's previous reprints she continues to maintain a respectable price tag. It's possible that this Aurelia printing could be more expensive than the previous ones due to its well-received new art. The only downside to this deck is that its guild lands are Mountains and Plains which are traditionally the least desirable of the basic land types. If you were on the fence about purchasing any of these decks I think this one is one of the best.
Selesnya
This deck is the one that might be the hardest to find for MSRP. The Selesnya deck has a retail value of $48 and a lot of it is in one particularly potent reprint. The stellar reprints in this deck include Trostani, Selesnya's Voice ($4), Tolsimir Wolfblood ($2.50), Hour of Reckoning ($3), and Privileged Position ($27). While it's not listed as a card in the deck, I also want to point out that this deck will also include a Voja token (created by Tolsimir Wolfblood) that has never existed. If the Voice of Resurgence elemental token is an indicator, Selesnya players take their tokens seriously and will pay for them. While I don't have an actual price to link to, I would be surprised if Voja was worth less than a dollar or two. Now let's get down to the card I know you want to hear about. Privileged Position is an exceptionally unique card as it basically grants all of your permanents hexproof. Similarly old cards like Asceticism and Greater Auramancy carry very large price tags. Privileged Position is the only one that protects everything and as such I don't really see the decks printed to meet that level of demand. My expectations is that even at its lowest it won't dip below $15. This deck is definitely the best value in terms of reprints and has a large array of legendary creatures and reprints to appeal to those with smaller collections. If you see this at MSRP I think you can't go wrong getting it.
Overall
I think these decks are pretty great. Obviously some of them have better reprints than others but they all celebrate what made each of the Ravnica sets great and are a good product for those looking to build their collection of older cards. I personally have purchased all 5 because I think the guild basics are really sweet and the border cards will look great in my Commander decks. From a financial standpoint they're pretty good at toeing the line between excessive value that causes MSRP to skyrocket and getting a good amount of value for you money.