I got my ProtoKits (2x42 1x41) yesterday and was able to tink with them a little after my wife and child went to bed. I did have to read and execute the ProtoKit guide's bootloading section, linked at the bottom of the kit product page, carefully to get the thing to work. I got weird results before that.
Anyway, it is an interesting mixture. I haven't worked with UDB blocks before. I'm a little hesitant about all the generated code, but at least you can see it all. The links to the datasheets for the modules are pretty handy too. And apparently you can even make your own UDBs.
I'm sure it will take some getting used to. The first thing I tried, putting a clock straight out on a pin, was a no go, for example. It has to go thru something to get to a pin. But I did get a compile error and the message was enough to clue me in to the fact that I couldn't push the clock directly to a pin even though the schematic drawing thing would like me hook that up.
I definitely think this chip will be worth the time investment to learn. (Time is one of my more valuable assets these days)