The 300 ohm has less signal loss but is a bit more susceptible to noise. I use 300 ohm into the house (50') and then convert to 75 ohm coax for the amplifier/splitter. From there, It's sent to four receivers via coax.

Should you choose to go 75 ohm coax all the way, most antennas are 300 ohm and you'll need to purchase a weatherproof 300/75 ohm transformer to mount on the antenna. It's only about $4 or so @ RatShack.