My experience has only been with Battleping but I'd say yes, it makes a noticeable difference. Made me go from being unable to avoid any AOEs without getting hit to being able to raid regularly alongside US players. That said, it worked well with ADSL but I don't know how efficient it will be if you have fiber-optic connection. Battleping has a trial mode that lets you connect for 20 minutes at a time, might try it out and see if it makes a difference.
As for comparison between the different services like Pingzapper, WTFast etc., other people here may have more experience with those, all I know is that Battleping did its job well.
