In a nutshell, don't bother.
Some friends recently organised an evening at Daidaiya in Akasaka. Not normally a huge fan of fusion izakayas in comparison to more 'standard' ones, but I was quite curious because I had read some good things about the place, so was happy to go along. However, the hype is absolutely not justified. We ordered lots of menu items a la carte, but apart from the buri kama (which was genuinely excellent), the rest was rather disappointing.
I read that - being a fusion izakaya - Daidaiya offers some exciting and unusual sushi. Some of it was indeed quite interesting (though not interesting enough to remember specifics, and it's only been about a week; I remember Korean seaweed featured, but that's it), but not sufficiently so to detract from the fact that the quality of the fish just wasn't very good at all. I glanced at the tired and depressed looking uni and maguro, both of which had clearly seen much better days, and wished I was in a little neighbourhood izakaya where the money that clearly went into Daidaiya's slick architecture had gone into quality ingredients instead.
Much of the remaining food was perfectly fine, but no more than that, and overpriced for what it was. If you feel you absolutely must visit this place, order three or four buri kama and nothing else. Maybe the place had an off-day, but in a city like Tokyo with its huge abundance of inexpensive izakayas with top quality fish and other food, Daidaiya is not good enough to justify the price tag.
I should say that maybe their other branch (or branches?) is / are very good - often different branches of the same restaurant chain in Tokyo differ quite a lot from one another, and I heard good things about the Shinjuku branch. But the Akasaka one was certainly a disappointment.