Sparx first shipped units to Kickstart backers around April 2016.
The Sparx guys are no dummies. They have done extensive testing of the product - to the point they even took the sharpener, put it in their Pelican carrying case, and dropped it like 200 times to see how durable the case was (https://youtu.be/j4eARLGSu3A). They tested freezing the unit to see if it still operated fine (https://youtu.be/DJ6qq86mALA).
I invested in the Kickstarter early because I wanted my own sharpener and I had some extra cash on hand. They stumbled on execution - they shipped months later than they had planned. There were constant excuses as to why the product was going to be later than they thought. For a while I was wondering if I was going to need to get my money back from Kickstarter escrow. But they did ship. And they obviously worked really hard to build a product they were very satisfied and proud of before they shipped. And for me, its been everything I hoped it would be. Four hockey players in my house (my wife recently started playing too!) and our two kids and myself haven't skated on a non-perfect set of edges since I got it. We're totally spoiled. The worse it gets now is when the boys have a 4 or 5 game road tournament out of province, and for that I sharpen their skates and their spare blades and they can swap them out if necessary.
Anyone that wants to criticize the Sparx should consider whether they are talking from facts and hands on experience with the unit, or whether they are just using conjecture to throw out reasons why they think some other solution is better for certain scenarios. For anyone who sharpens 1600 pairs or less a year, so far I've seen zero evidence that the Sparx is anything but a really solid solution.
colins