I have a good two-word dotcom domain that I first registered a number of years ago before interest in the Internet began to really grow.
I only have the dotcom version and I do not have the hyphenated version.
The first word of the domain ends with two letter "s" and the second word of the domain begins with a letter "s" which means there are three "s" letters together. This obviously introduces the possibility of misspellings of the domain by potential visitors.
Over the years, others have registered all the misspelled versions. Also, I have received a number of inquiries about purchasing my correctly spelled version.
The two word combination is a perfect fit for an industry of which I have strong knowledge and now I'm ready to begin developing a site for that industry.
Should I be concerned that I only own the correctly spelled dotcom version and others have all the other variations? Concerned enough to consider building my site using another domain? Or should I just proceed with the site and not be concerned about what others may do?
If it's a good domain that gets a lot of traffic I wouldn't worry that much about the others (but I'd backorder them). It's still a lot of traffic.
If you want your visitors to remember your spelling you will have to do some branding that emphasizes just that. Have a good, readable logo, use the full domain name lots of times in the text on your site.
You'll give some visitors to the misspelled domains but it can be minimized by spoonfeeding your visitors your domain name (in a non-offensive way..)