Well to be honest Kaijudo is alot cheaper than Vanguard, a competitive deck in Kaijudo would cost you about $30-40+ even though Base Set doesn't come out til next month as it just has the Dojo Edition Packs and 2 Player Starter Decks. A competitive deck in Vanguard would cost about $200+ which for people who've heavily invested in TCG's like Magic, Yu-Gi-Oh!, or Pokemon competitively will have difficulty branching out towards.
Unlike Vanguard, Wizards of the Coast announced that there will be "League Play" for Kaijudo similiar to what the Pokemon TCG has to help newer players into the game and get rewards as well. Kaijudo might also have a better Tournament Structure than Vanguard, last I checked Bushiroad doesn't allow Swiss Style Rounds in most of their Sanctioned Tournaments for Vanguard, just Best of 1 Double Elimination which is a huge letdown for me.
Some of the Vanguard players I talked to on Pojo don't like Swiss because they think playing all your Rounds like in Pokemon is pointless just to improve a Seasonal Record. They were like well If you lose in 2 of your rounds at least you get to play in Side Events, but this was just in one of the Events that Bushiroad was hosting. At the Anaheim Event for Vanguard, Bushiroad had a player turnout of over 400 people and here's a pic to prove it:
A Spike Brothers Deck also went 6-0 at the Event as well:
4 General Seifried
4 Juggernaut Maximum
2 Sky Diver
2 Jelly Beans
4 Panzer Gale
3 Devil Summoner
2 Dudley Douglas
4 Wonder Boy
4 Cheer Girl Marilyn
2 Medical Manager
Let's see a Kaijudo Event top that next month, I'd love to see it. I wouldn't doubt it since alot of people are getting out of Yu-Gi-Oh! for other TCG's and for those that haven't played Duel Masters in years this is their chance. You also have to remember that Duel Masters is the #1 Best Selling TCG in Japan right now even dethroning Magic and Yu-Gi-Oh! with over 40 expansions and counting although Pokemon TCG is like #2 or #3 over there of course. Cardfight!! Vanguard was released in Japan and Singapore just last year as it recently made it's way internationally to the U.S. and other countries as well.
For those that don't know about the rule changes for Kaijudo compared to Duel Masters, you can only run 3 copies of one card per deck and when you play a card in hand that shares a Civilization with a card in your Mana Zone you can cast it with other cards of different Civilizations without tapping the matching card for mana to cast the card you're playing. Deck Size Limit is 40, I believe you can run more than 40 cards per deck where as in Vanguard your deck has to be exactly 50 cards with 16 Triggers. Most Kaijudo players run a deck of 40 cards cause you have a better chance of drawing into what you need alot easier.
I like how there's more deck creativity and better ways to make a Rogue Deck in Kaijudo than in Vanguard, with Vanguard a Rogue deck is essentially a Mixed Clan Deck which most of the time will be inconsistent anyway considering that the game doesn't work like how you can team up cards of different affiliations like in Marvel/DC Vs. System. That way it'd be much easier to apply Trigger Boosts to Units that don't share the same Clan with eachother by "teaming up" those Clans, although you can boost a Unit that doesn't share the same Clan as the other though. Sure Kaijudo's card pool is very limited right now, but give it time as well as with Vanguard and you'll see the difference especially in how much you pay to build the decks of each TCG as well.