When I've seen people in Australia and the UK (and I think maybe the Grain to Glass guys in Canada) use these sorts of kits I've always wondered how they turn out, so curiosity got the better of me and I ordered the Citra Session Pale Ale kit.
To give it the best chance of success (and because why not) I'm planning to use my fermentation chamber, cold crash, and do a closed transfer to a keg, but other than that I'll just follow the instructions and see how it comes out.
I do mostly all grain nowadays but still do an extract batch here and there to experiment, and as others have said if this is a super quick way to crank out a beer and the results are decent, or at least are on par with typical extract brewing and is a lot faster, to me it's just another tool in the toolbox.
I'll report back on the results and hope the others trying will do so as well!