Signspot, your post is helpful to me. I never went the Flexi route, I did not know at the time we bought our machine that a fully useable trial version was available. Plus, I'd read about so many problems with the Flexi and L25500 that I was simply hesitant. Got enough headaches already!
I am giving Onyx a trial still. Fortunately for me (after all the initial stuff... waiting for delivery, getting electrical setup, working through software issues and bugs, then just setting up the right profiles and learning to work the machine) we are finally getting some good prints. I am happy with the printing now, but I do wonder if it is worth a try to compare the Onyx to Caldera. I'm just not ready to buy yet. Fortunately, the people at Onyx are patient and willing to extend the trial out a bit longer. I have appreciated this as I think the learning curve is pretty big.
I feel like I just started to get Onyx to work well, but not using canned profiles for most stuff. So now I am liking what I'm able to print with Onyx, but can't say it was so easy to learn, but learning by trial and error and lots of wasted prints! I have not tried Caldera, so cannot make a comparison yet.
The fact that Caldera needs either a Mac or Linux is really not a deterrent to me. I have used Mac quite a bit in the past. I'm willing to do it again. But Ben at Caldera did tell me that if I load Linux on a PC station, it would wipe out all the PC files. I think that is how he put it. I'm just not sure I want to do that yet! Oh, computers!!