I would run the longest I can
Find out where your repeaters are located before choosing the antenna. If the repeaters in your area are located on tall buildings or hills, you will not gain much by using antennas longer than 1/4 wave. Happy_Hamer on this site has an interesting story about how he could not hold repeaters in downtown Chicago with his 5/8 wave antenna, but had no problem with a 1/4 wave. Most of the repeaters in downtown Chicago are on the top of the buildings.
1/4 wave antennas are cheeeeeaaaaap!