The website says that it is designed for screens at least 17inches. However, I have a laptop with a 14 inch screen, and it looks fine.
Here is the default view for one individual from the Royal Family database (over 3000 entries) that came included with the demo:
I like that I can see several generations on my screen at once, and to move to a new person, I just need to double click on their name. You'll notice if you enlarge the image above that at the top of the screen in the right is a switch for 'Levels' set to 3. That's the number of ancestor generations. It can be increased, but on my screen it get rather tiny with anything higher than the default '3'. (So, yeah, a 17 inch screen might be nice. But 3 generations is great.) You may also notice the colors and fonts for the interface are easily adjustable from the default view. If you click on the tabs you see at the bottom of the screen, you get different information in the bottom half of the screen.
It is extremely intuitive and easy to navigate.
Also, I really appreciate that the database is either updated as you enter the data, or it is saved when you close the window (instead of quitting from the file menu as one really should always do, but sometimes you get in bad habits.) When you close the window by clicking on the red circle, a dialog pops up asking if you want to close the window, close and quit the application, or cancel. MacFamilyTree just closes the window automatically, and all unsaved data is lost.
Finally - there's a cool "On this Day" feature that tells me that King Louis XVIII, Mary Stuart, and Charles V the Wise all died on September 16th. I can also get a list of births, deaths and marriages for a given month, which with my own family database, could be useful to remember when I should go out and buy gifts. (I'm not likely to buy gifts for anyone in the Royal family.)
You also can't save a report in "Register" format. You can't do this with MacFamilyTree either. (I've read you can do it with Reunion, but that's three times as expensive as iFamily, and more than double MacFamilyTree) I find Register confusing, but still, it is supposedly the standard.
I like iFamily's reports. Their descendant report covers each branch of the tree separately. So in the Royal Family example, if you started with the Queen, it would list Queen Elizabeth, then her son Charles, then his children William and Henry, and then if eiher of the Princes had children, their children, then it would go back up to Charles' sister Anne, then her children Peter and Zara, then back up to Charles' brother Andrew, etc. It's certainly easy enough to read and follow the report.