well I own both now. I just received my spectra a few days ago, so I have had limited time to put it through the ringer. But in truth I have to say its a hard set to compare. Its like comparing a mountain bike and a street bike. It all depends on your intended use and how your current style fits these machines. So ill try to highlight what I have come to love about both machines. Centri : is a great machine, I've used it to color pack and blend beautifully. Black&grey has been no problem at all, very smooth and consistent. I like being able to adjust the stroke length and strike force so easily. The only downsides I found is that there is a bit of a learning curve. It takes some time to figure out what settings work best with your hand speed and technique. But once your able to pinpoint them, its like a paintbrush. I have lined with it using a tight 5 but it is not my go to liner to be honest. Still love it though. Spektra: this one is a nice machine, a damn nice machine. Its give system works very well and seems to give right where it counts. The design of the machine shows some ingenious simplicity. The kind that only comes from a ton of redesigning and editing. I have lined with it, it has replaced my rapier2 as my go to liner for now. Shading is no problem, reminds me of shading with a dragonfly but it seems to be faster. Color is easy and quick. And saturating an area is no issue at all, and thats ith the 3.2mm stroke. Both are smooth and very well built. Both designers obviously put alot of thought into these to make them the bast machine they could be for the artists that use them. Its a very hard comparison but make your decision based on what you need the machine to do. I hope this helps.