I haven't tried any of the recipes in the book, but I think the methodology is questionable (in the BYO article, too). Don't mash too low, unless you want a thin beer. Use shed loads of active wet yeast (as apposed to dry yeast with up to a 48h or longer 'lag phase' expected) and don't bother aerating the wort well, as recommended, because you've pitched enough yeast to go straight to fermenting the wort to FG. No need to aerate/promote much cell growth at all. Nor is there any need to pitch a kveik, turbo or any other distiller's yeast strain and ferment at a relatively high temperature. Ferment close to the recommended upper temperature of the yeast you pitch, at most. If you've pitched enough healthy yeast fermentation should be done within 2-3 days. Unless it's your aim there's no reason to brew a piddly little beer either. I've had very good results up to around 1.050 and others claim up to 1.060. The biggest game changer has been the availability of affordable pressure capable FVs and reliable spunding valves, though. Conditioning can be finished by the end of fermentation by either fermenting under pressure or naturally carbing using the last several points of gravity. A good yeast choice is going to flocculate quickly to produce bright beer, especially if the temperature is dropped a tad. It's possible to get a very good beer into a glass within 5 days or so. It's not something I aim for generally, but it's a fun challenge to test your skills as a home brewer. So, yes, speed brewing does work. It's a little bit like brewing like a scaled down commercial brewer. I think my best so far has been a crisp, crystal clear Czech Pilsner (6.8% ABV) fermented with WLP800, which took about 2 weeks. I wouldn't bother comparing it with 2 day old funky kveik dishwater, to be honest. I don't think there'll be any comparison between said dishwater and a 5 day old English ale fermented with an English yeast strain.