We have used it for years and I like it. It is a bit of a pain I will admit, but only because you do need to print out everything…and I am less organized and more lazy than I would care to admit so it’s not always ready to go when I want my kids to use it. But of course, the reason why it’s kind of a pain is also the reason why I wanted it in the first place — to be able to customize it and have the flexibility with quotes for copywork, etc. It’s just not “open and go” by its very nature.
I love being able to choose the font I want for each child (each of my kids tends to use something different that is just a personal preference or a better fit for them individually), and all the other customizable details — point size, density of line including dotted or solid, starting dot option, arrow option, type of lines, etc. It is invaluable when my kids are transitioning to cursive, or even after a break from writing, like after a few weeks of vacation when my cursive writers are a little rusty.
We’ve used it for Spelling Wisdom passages (when, at times, we use it for copywork, or even sometimes to model cursive while preparing for dictation), scripture passages, literary quotes, poems, inspiring quotes from talks, hymns, memory work, etc. We tend not to use for their own personal writing (like where they might narrate/dictate to me, I type it up, then they trace it as a “written” narration), although I know families who do that regularly. Currently two of my kids are using it with their passage typed out in their selected font on the top of the page, then blank sets of lines following the model where they write out the passage. Sometimes they have to trace the model first, sometimes not, depending on what the need is en route to developing better handwriting. (Oh, another nice thing is that if you have 2 kids doing different fonts but the same passage, you can just change the font of the passage with a simple click of a button — no highlighting text first or anything.)
ETA: One thing that is nice if you are working from PDF or online passages (like a Spelling Wisdom PDF or a reliable online site for scriptures, quotes, etc.) is that you can just copy and paste into the StartWrite, thus minimizing the risk or typos when you are quickly typing something up yourself. Sometimes scripture verses get messed up if there are little footnotes (a,b,c) within the verse itself, but everything else tends to paste in nicely.