I actually use CLIP Paint Lab for my arts regularly. (Since my OS is Mac OSX, it's the closest thing I can get to Paint Tool SAI without using a Virtual Machine or Bootcamp.)
Currently, Version 0.7 is out and available to download. For those who had the previous version, they added a vector line tool, fixed the water tool up to look less underdeveloped, added some brushes from Illuststudio and a few minor changes. I'd imagine in the future that CLIP Paint Labs 0.8 and 0.9 will be having big changes until the release version comes out. (It probably won't be free, but I can't imagine it being very expensive.)
CPL is like SAI in so many ways. For one, it starts up really quick, which I think anyone would like. It does start off with a default canvas, but you can either close it and make a new one, or change the size of the canvas. It has the very similar brush tools, water tool, pen tools, rotate, zoom and undo/redo buttons, so the transition from SAI to CPL was an easy one for me. I even found that you could change the smoothing with the tool options, which was very much like SAI as well.
I do agree that CPL is harder to use since it is in a language that I don't fully understand, but I have found that it does have menus very similar to Photoshop, which helped me a lot. Because of that, I've been able to figure out how to do many things. If we could get this program translated, there'd be so many more things we'd be able to do, since this can be an advanced program. I do hope to make a tutorial just for CPL, but there is still more to learn about it.
But yes, CLIP Paint Lab is a very good program so far in it's development. I can only imagine how much better 1.0 will be when it comes out. It makes a very good rival to SAI, considering that it supports both Windows and Mac and CLIP is offering updates, similar to Illuststudio.
If anyone has any questions about the program, I can help!