Sit Where You Please?

I'm currently in a debate with myself about how we're going to seat guests at our wedding.
Option 1: Assign seating with place cards and table numbers (the more traditional route.)
Option 2: Let everyone sit whilly-nilly as they please.

There seem to be two schools of thought when it comes to seating people at weddings (from what I've seen on the numerous wedding blogs I've read.) One says that by telling people where to sit, it allows for families and friends to mingle and mix, something they may not do on their own. This might be the only time that this group of people is together, so you might as well make them interact and get to know each other.

The other side says that by allowing people to sit where they want, friends get to sit with friends (which is nice after college when everyone is scattered around and may not get to see each other often,) families can mix and mingle as they want instead of being pushed together, and its one less thing for the bride to worry about. 

The way I see it: 

Option 1: Assign seating with place cards and table numbers (the more traditional route.)

Pros:

• this ensures that there will be enough places for everyone to sit. 
• it deters people with a large party or family from taking over an entire table and leaving a random space or two
• woohoo more DIY projects (table numbers and place cards)

Cons:

• I have to actually figure out a seating chart
• I don't want to make people sit with someone they don't know. Maybe it's just me, but I like to meet people on my own terms instead of having to sit with them awkwardly at dinner. 

Option 2: Let everyone sit whilly-nilly as they please.

Pros:

• People get to pick who they spend the majority of the night with
• Friends and families can re-connect over dinner
• I don't have to worry about making a seating chart
• I can still dress up the tables with other DIY projects that don't include table numbers. 

Cons:

• The biggest thing I'm worried about is that a large family or group of friends will sit together and take up the majority of the table leaving only one or two spots left. This could deter people from sitting there and couples or families may have to split up to find spots to sit. 

When Keegan and I originally talked about seating, we decided to allow people to sit wherever they wanted. We didn't care about assigned seating and we wanted our guests to be comfortable so we just decided to let people take care of themselves. I think I'm still leaning towards the sit-where-you-please route, I'm just worried that it's going to cause some awkward seating problems.

Anyone have any opinions? Did one way work over another for you? I mean, I figured that assigned seating has been used for so long that there must be some rhyme and reason for it, right?