I write every day, both professionally and for leisure, and I use the free version of Grammarly.
With articles and creative work, Grammarly is great as a second-pass to catch anything that Word’s native checks miss.
It’s also absolutely invaluable when it comes to cleaning up correspondence and writing on websites (like Quora). I have it set up as an add-on to the Chrome browser.
I’d use it on my iPhone, but they require me to change my keyboard and I’m not willing to give up the one I use.
The paid version has a considerable number of additional checks that take you deeper into editing chores. I’ve used the pay version before and it does have value, but the price is a bit steep in my opinion. If you’re the type of person who wears a monocle and eats caviar non-ironically (or you make a lot of money writing), then the paid version might be a good option.
For deeper analysis, I invested in Pro Writing Aid which does similar work for a fraction of the price of Grammarly.
And for those of you playing the home game, that means that I do three checks on spelling, grammar, and style before I show my stuff to anyone else (and I still make mistakes)!
I wish everyone used the free version of Grammarly at least. It would clean up 90% of the simple fixes I see. (The Grammarly add-on is indicating I’m in good shape while I write this piece, and caught four things for me this time.)
For those people who are doing more important work and want some deeper analysis, Grammarly is a quality option if you have the cash.