I'm currently building up Dark Irregulars, Pale Moon, and Dimension Police, and have the two trial decks as well. I'll probably build Bermuda Triangle and Oracle Think Tank once i get the other clans solidified.
Overall, it's pretty fun. Games go pretty fast, but they're slow enough to be able to actually enjoy the games. Each clan has it's respective combo and theme, so it's relatively easy to be able to predict and block combos, especially when a lot of the big abilities and chains trigger off actually hitting.
As far as the two trial decks go, both are pretty well made. Main problems are that the Kagero tends to end up with the Grade 3 9000 Pow Vanguard too much, and Royal Paladins only have one Blaster Blade in the deck. Will probably pick up the Nova Grapplers and OTT trials once they come out too.
The main thing I don't like about the game is that bushiroad's obviously boosting the main character clans and not paying as much attention to the other ones. Luckily Royal and Shadow Paladins, and Kagero are going to stop getting cards come next set, and Granblue is getting some much-needed support. Hopefully Nubatama also becomes playable. There's also a bit that each clan generally has a solidified strategy, and since it's not easy to combine clans, you're pretty much locked into one type of playstyle.
Another thing that interests me is that bushiroad plans to do simultaneous set releases for both English and Japanese versions of the card game starting next set (Late April), and that the rest of English sets will probably catch up by July.