Yeah it's annoying the pages keep taking a poop. Especially during guild activities where timing is important.
I had no intention of trying out DP when it first came out. But someone needed help running the game in Firefox when it clearly said Chrome only right next to the start button. Face palmed so hard.
The UI is horrible but it looks much better with their recent release of their SFW version called Dragon Apocalypse on DMM (1, 2, 3). The UI operates much smoother with <1s animations and doesn't feel like someone's first html project in grade school. In CB there are individual buttons for everything instead of it being all displayed at once (damage, guild chat, etc) and doesn't really interrupt the flow of battle opening them.
That being said, I enjoy CB/RB in DP quite a bit and as mentioned is the only real reason to play the game. It made me regret not giving the game a chance when it first came out because of the UI. When Nutaku updated the site and it showed DP in top 5 which baffled me but I see why now.
DP is a low maintenance game in terms of burning AP/stamina since you can skip. There are multiple time brackets for CB that can be adjusted by the guild master which makes it easier to accommodate people and avoid certain guilds. AP potions are necessary for guild activities but can be easily farmed by just assisting in kills on the raid screen. I usually just sit and refresh the My Page which also lets me know when my own raid boss dies. There is also a deck building aspect since every card has 3 skills. When in combination can create unique decks based around doing full damage or full supporting from the rear line.
Not sure how much longer I will play it because I had every intention of peacing out when I hit 100 Juno kills. But I joined a decent guild that's experiencing all the content and it's quite refreshing.