I saw this recently and just fell over buying it.
It's the expanded version of the Trio, and it's ability to render Bass & Drums is too cool.
I'm using it solely as a song-writing inspiration, so my learning curve is much easier than a performing user.
That said, it didn't take me long to get the particulars up of laying down riffs for song parts (where Trio+ learns your riff and generates Drums to it's rhythm and Bass to it's chord structure) and then creating the loops (where you record those riffs so you can then solo over them)
I was impressed with it's ability to roll with some more complex chords. It didn't hiccup or nothing.
This is such a great tool for introverts and sociopaths who can now tell their drummer & bassist to jump in a lake.
But I am 100% sure that real people would stir much more creativity than this box. That said, it's a jump forward in song-writing tool evolution, and the Trip+ has many more options than the Trio if you are into writing anything-at-any-time. Probably overkill, but it's worth the price if just for the Loop expansion and it's long time.
I haven't paired it with the Kemper yet, but there are a few threads here that speak to such pairings if you Google search them.
Bottom Line: IF you are thinking of buying this, it's worth the price. If you haven't heard of it, it's one of those gadgets that are a pure joy to use. Probably the best guitar gadget invented short of the Kemper, but the best guitar gadget for songwriting.