I recently came in second at one of my local store championships with my bloomlord/rafflesimon deck, so I have been trying out Sakuyamon instead for a little while. This has largely been against my fiancé, who was on Xros Heart but has now been forced to switch to Blue Flare due to the upcoming hits (premature, imho). My thoughts:
-The deck is too big brained! You have to play 4D chess in your head just to get a second security check. It is wild. I had thought that with the new support from BT10 it would get easier, but if anything the new search Renamon just makes things more complicated since you are more likely to bottom-deck digimon you need.
-When it comes together it is really cool! There is very little the deck cannot handle, except Wyvern's Breath and Sunrise Buster (or any DP reduction). The new plug-in that gives blocker is also really strong, especially if played off of Maid Mode. Maid Mode also lets you swing for 4 checks if you have her, a regular Sakuya, and some plugins!
-There is almost no punish for swinging at it! Unless you decide to run Wyvern's Breath, which good luck finding room for, your opponent basically can't lose swinging into security.
-Deck building is really hard, because everything is required and useful. There are many yellow options that would be cool (I think Eden's Javelin could be spicy under the right circumstances), but you have to run so many Plug-in S (the green digivolve one) that it is hard to justify.
-Is it competitively viable: If you can make it past the first two rounds of a tournament without giving yourself a migraine, I think it is ok. It definitely has some really really bad matchups, particularly decks that don't care about DP reduction (Jesmon). But it can handle blue flare really well since they have few options if you only put one big stack out.