Testing on the public network is actually a really poor test, in fact.  It doesn't test a gamut of difficulties, it doesn't test large block sizes (most pools are only generating 250k blocks right now), it doesn't test large coinbase transaction sizes, it doesn't necessairly tell you that your devices have severe latency problems (isn't obvious on the public network with a short test, but kills you if you want to merge mine with a fast chain).

Several miners have shipped from hardware makers with firmware which had severe problems with larger blocks as a result of inadequate testing.

I'm also of the opinion that testing should generally not be done on the public network, and that any "testing" done on the public network for demonstration or burn-in purposes should be limited to small amounts and ought to be 100% paid to the customers. Anything less creates creates a conflict of interests.

But hey, in a free decentralized system no one can dictate the terms from the top down. So if we want good conduct from hardware makers we're going to have to demand it as a community, or just hope that they'll adopt it on their own to foster goodwill. ::shrugs::

In any case, great to see that CoinTerra has hardware up and hashing.