I have one of each and find they both excel in different circumstances and sometimes I use both at the same time (one for the chicken loop and the other for the flagging line). The KITEBUDDY seems beefier and though harder to screw in really is a beast when screwed all the way down. I have not been able to screw it in in some locations due to hard stony sand and the Buddy's diameter. Or it is really hard to screw in and you can get fatigued doing it...
The KITEANCHOR is easier to screw down and works better in harder sand. It does not seem as beefy since it's diameter is much skinnier. So it can move a bit but I think it would stay under a hard tug. The BUDDY wouldn't budge I believe at all. If I could only get one it would be the KA because of the hard sand issue. However I'm glad I have both...