Most of all, times chosen for you. A free search finds a time that is good in general. The paid plans also check every time against the birth chart of each person involved — the star and Moon sign you were born under, and the sign that was rising when you were born. They set aside any time that works against one of you and rank the rest by how well they suit you, so a wedding time suits both the bride and the groom. They also run the deeper check of the sky over the event's city at the exact minute it begins: for weddings and house-warmings on the 7-Day Pass, and for every event on Standard.
Both plans also show the dates and times to avoid, with the reason for each. If nothing in your range works, they tell you the next date that does. They look 6 months ahead instead of 3 months, and let you search as often as you like. The 7-Day Pass shows your top 3 windows. Standard shows every window we find, adds night-time windows, and lets you sign in on any device with just your email.