If it's not really about tuning or wiring. Then it belongs in here.
Which manufacture makes the best dynamometer?
It depends on support in your area. Did you watch this recent webinar on how to choose a dyno?
One that works - see above ;-)
Seriously, though, there are MANY different types, that have MANY different applications, and you really need to have a good idea what you want to use the dyno' for.