Lab Gruben 13000 Vs FFA10k Vs Infinite 8

Okay cool, it'll be at the Volks.

Will let you know more at the end of the week 

I don't suppose the best-sounding bass amp in the world is any match for any Lab Gruppen if it spends most of its time at the repairers!

million dollar question, that!

Difficult to be scientific. I only see amps when they go wrong. That's a skewed view of the amp world! I can only tell you what amps are made with love and care and the best components and which are thrown together with cheap chinese rubbish parts. That doesn't always mean that the one type is more reliable than the other...though its a guide I suppose. I don't know how they're treated out in the field. I don't know how many units of a particular type are out there...the best-selling amp is bound to produce more failures due to shear volumes of sales.
As an example, I get alot of Mackie SRM450s for repair. They are I believe officially the world's best-selling powered plastic speaker...what's the reason they're a frequent visitor? Because they're unreliable, or because theyre so numerous?

A volume reseller like Blue Aran are perhaps better at answering this sort of question, because they will know what works out of the box, what fails under warranty, and what are the brands they never see come back.

Some manufacturers (and this goes for lighting as well as sound) will squeeze every last morsel of power out of their components to acheive performance at the sacrifice of reliability. I've just repaired some LED moving mirrors that worked (and no doubt sold themsleves) brilliantly until they were safely out of warranty whereupon the LED chip arrays died. Turned out they were so bright becuase they had over-run the leds for maximum impact and minimum reliability. I soon modified that! I'm sure you get the idea.