My understanding is that one of the problems with a higher tickrate is that the weapons balance is altered from what the game designers intended. Typically, the mingun and pulse rifle do more damage in a shorter amount of time. There is a mutator that claims to address this.
Its called CBTIW & AB - ClanBase Tickrate Independent Weapons (TIW) & Anti(?) Boost). You can get it at
http://www.clanbase.com/miscdl.php?did=797
Some commenters on that page seem to think that is can mess with UT's net code (no idea how it will interact with the UTPure update if and when it comes) but I haven't noticed any negative effects. Anyone else have experience or feedback?
This mutator introduces two completely new weapons (TIW_minigun2 and TIW_pulsegun, IIRC). Players who have keys bound to "GetWeapon botpack.minigun2" or similar will need to change them to "SwitchWeapon 7". This setting should work on all servers, whether or not they're running TIW. PulseGun seems unaffected.
I have it installed on my server (Windows server, tickrate 35) and it does seem to help somewhat.
Personally I love playing on a higher tickrate server. Checkout the UT netcode tutorial here on unrealadmin if you haven't already. It has a wealth of info.