To create a task, I use com.calengoo.android.CREATE_TASK
You can send the following as part of the intent: "title", "note", "priority", "duedate" and "tasklist
I could easily add any of the fields to my IFTTT message but I kept it simple and just use title and duedate.
Check out this link, towards the bottom for more info: http://android.calengoo.com/pagedoc/pageadvanced/styled/pagetasker.html
Now my turn to ask about intents...curious which ones you send to get the info you mentioned?
For private use, CalenGoo - I found it a long time ago and at the time it was the only calendar where you can set reminders to use alarm sound channel (which means they will actually play the sound even in silent mode). Possibly other new calendars have this function now too, I don't know.
I also have TimeTree installed, because that's what my wife uses on he iPhone and it allows us to share our schedules.
CalenGoo is by far the most powerful calendar app. However, you have to take some time to adjust everything you want technically and visually. Documentation: http://android.calengoo.com/pagedoc/pagedoc.html
I've purchased Business Calendar but haven't had it installed for a couple of years. Maybe I'll try it again but the last time I tried I couldn't give up floating events. It's the one feature people don't realize they need until they have it, imho.
And yeah, Pimlical is as ugly as it is functional. I have a hard time getting past the design too, but it's ridiculous the amount of power-user features and customizability it has. Overkill for most people for sure but it's worth looking into for anybody that feels like they'd like they're missing some capabilities in the more popular calendar apps. It's kind of like what Foobar2000 is to desktop media players.