We had a Friday wedding. It definitely was not because it was cheaper, but because the date had a special meaning. Luckily it was a national holiday, so most people were off work. We had a fairly small wedding, around 100 guests. We only invited close family and friends, so everyone we invited came (even a few we did not invite) Afterwards, we heard from a lot of our guests and they told us they actually liked the fact that they still had the weekend to do things they needed to do.

I think Friday weddings are a great option for some folks if the venue/caterer/etc are cheaper due to it not being a Saturday.

That said, it is hard for us to take time off to travel for a wedding, so we are more not likely to attend a Friday wedding if it is out of town.