We will need to ponder on how to import recipes from other recipe management software. We do it for books from Good Reads, LibraryThing, etc but they are set up for export of the ISBN numbers so it is quite easy. Recipes don't have a unique identifier so that will be an issue. And I'm not sure how easy these programs make it to extract your data - I would think they don't really want you taking that to another program. As a user, are you aware whether they have an export data function?
A major issue I can see would be the mapping of ingredients and categories to our database. I know how difficult this can be with the data we scrape from blogs - if they spell the ingredient name differently then it doesn't map and we have to enter it manually. Ditto the categories. So you may find that you don't save a lot of time as you have to manually check and edit all your entries.
You are right, we should explain in FAQs that using the Ingredient filters in Only show is much more precise - we will add it. The word search box is just that - it looks for the word you entered in ingredients, recipe name, book title and author name. It also looks in linked alternative ingredient names. So if you search by beets you will also see Swiss chard as an alternative name for Swiss chard is silverbeet. But filtering by root vegetables/beets in Ingredients will show only recipes with beets/beetroot.