They're just one example where innovation in the space is producing cheaper and more reliable tracking. The basic idea is instead of having per panel tracking devices, rather, use a simple robot run around a fixed track and adjust the panels as needed. Then repeat again and again, throughout the day. If the robot malfunctions, swap it for the spare.
- you need more space otherwise the panels will shade each other
- more components -> more cost
- more components -> more can break (and will break)
Swapping the robot for a spare is a very costly operation and can negate the power output by the panel whose robot malfunctioned over its entire lifetime after subtracting initial capital cost.
And that's assuming that you will be able to obtain 'the spare' 10 years after you put the whole system into service.
http://castillium.co.uk/tracking-solar/tracking-250kw/
So qbotix might have good solutions for the issues you mention. And that is of course without having concentrated solar power, which makes a qbotix a more attractive offer.
Whether this company did this or not is unknown, if they are offering this system on a per month basis, it makes sense they did some reasonable level of analysis of costs, because it would reduce their risk greatly.